It can be concluded from the third par...

Men and women may need to be treated differently when it comes to pain. Researchers in California have found that certain painkillers provide greater and longer-lasting relief for women than they do for men. This suggests that the physiology of pain differs between the sexes. The discovery could lead doctors to change the way they prescribe analgesic drugs. In controlled experiments, women often report higher levels of pain. But when it comes to prescribing and developing new analgesics, medical science usually ignores the sex of the patient, says Jon Levine, a specialist in inflammatory diseases at the University of California, San Francisco. Levine says that sexual differences were the last thing on his mind when his research group started studying a class of analgesics called kappa-opioids, which are chemical cousins to morphine and heroin. The researchers found that the drugs were less effective in controlling pain than their better-known kin(家属). But when they tried to publish their results, an expert reviewer spotted the fact that some of the treatment groups contained more women than men, and suggested that the researchers reanalyze the data to see if this accounted for their results. "To our surprise, all the effect could be ascribed to sex," says Levine. To test the effect of sex directly, Levine’s team recruited 20 men and 28 women who were due(预订) to have their wisdom teeth removed. After surgery, the patients first evaluated their pain as the origin alan-aesthesia wore off, and then every 20 minutes after they were given a shot of a kappa-opioid. The link between sex and the effectiveness of the drugs was clear, the researchers report in this month’s issue of Nature Medicine. Although the women reported a higher level of pain shortly after surgery, 20 minutes after a dose of the opioid their pain had lessened to a greater degree than it had for the men. And the women’ s pain relief continued for hours after the drug’ s effects began to wane in the men. "I’m very excited about this result," says Karen Berkey, a pain researcher at Florida State university in Tallahassee. In addition to sex differences, she would now like to see researchers explore other factors—such as age that might influence the effectiveness of painkillers. If scientists can understand why such differences exist, it may be possible to develop "designer" painkillers tailored (适应) to particular types of patient. Levine says the findings should prompt researchers to reexamine drugs abandoned as useless simply because they did not work in men-only trials. Whatever the outcome of the research, Levine says that a lot of the credit is due to the unknown reviewer who readjusted the focus of his work." Everyone in the group is appreciative," he says, "we’ re just sorry reviewing is done anonymously (匿名方式) and we couldn’t thank this person."As the research indicates the efficacy of analgesic drugs______.

A．may vary with sex
B．may be related with the degree of pain
C．are not decided by doctors but by patients
D．have nothing to do with sexual differences

单项选择题

Men and women may need to be treated differently when it comes to pain. Researchers in California have found that certain painkillers provide greater and longer-lasting relief for women than they do for men. This suggests that the physiology of pain differs between the sexes. The discovery could lead doctors to change the way they prescribe analgesic drugs. In controlled experiments, women often report higher levels of pain. But when it comes to prescribing and developing new analgesics, medical science usually ignores the sex of the patient, says Jon Levine, a specialist in inflammatory diseases at the University of California, San Francisco. Levine says that sexual differences were the last thing on his mind when his research group started studying a class of analgesics called kappa-opioids, which are chemical cousins to morphine and heroin. The researchers found that the drugs were less effective in controlling pain than their better-known kin(家属). But when they tried to publish their results, an expert reviewer spotted the fact that some of the treatment groups contained more women than men, and suggested that the researchers reanalyze the data to see if this accounted for their results. "To our surprise, all the effect could be ascribed to sex," says Levine. To test the effect of sex directly, Levine’s team recruited 20 men and 28 women who were due(预订) to have their wisdom teeth removed. After surgery, the patients first evaluated their pain as the origin alan-aesthesia wore off, and then every 20 minutes after they were given a shot of a kappa-opioid. The link between sex and the effectiveness of the drugs was clear, the researchers report in this month’s issue of Nature Medicine. Although the women reported a higher level of pain shortly after surgery, 20 minutes after a dose of the opioid their pain had lessened to a greater degree than it had for the men. And the women’ s pain relief continued for hours after the drug’ s effects began to wane in the men. "I’m very excited about this result," says Karen Berkey, a pain researcher at Florida State university in Tallahassee. In addition to sex differences, she would now like to see researchers explore other factors—such as age that might influence the effectiveness of painkillers. If scientists can understand why such differences exist, it may be possible to develop "designer" painkillers tailored (适应) to particular types of patient. Levine says the findings should prompt researchers to reexamine drugs abandoned as useless simply because they did not work in men-only trials. Whatever the outcome of the research, Levine says that a lot of the credit is due to the unknown reviewer who readjusted the focus of his work." Everyone in the group is appreciative," he says, "we’ re just sorry reviewing is done anonymously (匿名方式) and we couldn’t thank this person."Levine implies that the doctor is supposed to______.

A．take men’s pain seriously
B．use kappa-opioids to kill pain
C．pay attention to women’s pain
D．consider sex while prescribing painkillers

单项选择题

Men and women may need to be treated differently when it comes to pain. Researchers in California have found that certain painkillers provide greater and longer-lasting relief for women than they do for men. This suggests that the physiology of pain differs between the sexes. The discovery could lead doctors to change the way they prescribe analgesic drugs. In controlled experiments, women often report higher levels of pain. But when it comes to prescribing and developing new analgesics, medical science usually ignores the sex of the patient, says Jon Levine, a specialist in inflammatory diseases at the University of California, San Francisco. Levine says that sexual differences were the last thing on his mind when his research group started studying a class of analgesics called kappa-opioids, which are chemical cousins to morphine and heroin. The researchers found that the drugs were less effective in controlling pain than their better-known kin(家属). But when they tried to publish their results, an expert reviewer spotted the fact that some of the treatment groups contained more women than men, and suggested that the researchers reanalyze the data to see if this accounted for their results. "To our surprise, all the effect could be ascribed to sex," says Levine. To test the effect of sex directly, Levine’s team recruited 20 men and 28 women who were due(预订) to have their wisdom teeth removed. After surgery, the patients first evaluated their pain as the origin alan-aesthesia wore off, and then every 20 minutes after they were given a shot of a kappa-opioid. The link between sex and the effectiveness of the drugs was clear, the researchers report in this month’s issue of Nature Medicine. Although the women reported a higher level of pain shortly after surgery, 20 minutes after a dose of the opioid their pain had lessened to a greater degree than it had for the men. And the women’ s pain relief continued for hours after the drug’ s effects began to wane in the men. "I’m very excited about this result," says Karen Berkey, a pain researcher at Florida State university in Tallahassee. In addition to sex differences, she would now like to see researchers explore other factors—such as age that might influence the effectiveness of painkillers. If scientists can understand why such differences exist, it may be possible to develop "designer" painkillers tailored (适应) to particular types of patient. Levine says the findings should prompt researchers to reexamine drugs abandoned as useless simply because they did not work in men-only trials. Whatever the outcome of the research, Levine says that a lot of the credit is due to the unknown reviewer who readjusted the focus of his work." Everyone in the group is appreciative," he says, "we’ re just sorry reviewing is done anonymously (匿名方式) and we couldn’t thank this person."In their studies the scientists were surprised to find that______.

A．the women reported higher levels of pain
B．the women did not respond to kappa-opioids
C．kappa-opioids were not effective like morphine and heroin
D．sexual differences decided whether kappa-opioids were effective

单项选择题

Some problems can be readily identified simply by looking around. These problems concern the pollution of our environment by technology as a result of sudden upsets in the physical, economic and social balance. The most obvious of these are the general pollution of our physical environment and the destruction of irreplaceable natural resources. Not so obvious as these, but just as painfully significant to some, are the disappearing and changing of jobs which overnight often create large groups of jobless citizens. Can technology be used to undo what it has done, replace what it has destroyed or substitute for what it has caused to disappear No one knows. Many wonder whether or not all of the sources of pollution have yet been identified, whether or not they are being arrested and whether or not they will be prevented from recurring. Another set of problems relates to what technological advancement has done to the quality of life. An improved social life has not been unfortunately, either the goal or the chief beneficiary of technological change. Rather, any improvements that have occurred have been more accidental than intended. Too much has happened too fast. The changes demanded of marriage and family relationships remain largely unexamined. It is often a matter of "put up or shut up", and a person has to adapt his lifestyle to ever-changing conditions with little time for choice. The "no-move-no-advancement" type is an example of one such problem. Many people are coming to think that the reward is simply not worthy of the struggle, and they are taking jobs with less responsibility and lower pay.In the first paragraph the author is mainly talking about______.

A．environmental protection
B．environment and technology
C．technology producing obvious and insidious problems
D．the advantages and disadvantages of technology

单项选择题

Men and women may need to be treated differently when it comes to pain. Researchers in California have found that certain painkillers provide greater and longer-lasting relief for women than they do for men. This suggests that the physiology of pain differs between the sexes. The discovery could lead doctors to change the way they prescribe analgesic drugs. In controlled experiments, women often report higher levels of pain. But when it comes to prescribing and developing new analgesics, medical science usually ignores the sex of the patient, says Jon Levine, a specialist in inflammatory diseases at the University of California, San Francisco. Levine says that sexual differences were the last thing on his mind when his research group started studying a class of analgesics called kappa-opioids, which are chemical cousins to morphine and heroin. The researchers found that the drugs were less effective in controlling pain than their better-known kin(家属). But when they tried to publish their results, an expert reviewer spotted the fact that some of the treatment groups contained more women than men, and suggested that the researchers reanalyze the data to see if this accounted for their results. "To our surprise, all the effect could be ascribed to sex," says Levine. To test the effect of sex directly, Levine’s team recruited 20 men and 28 women who were due(预订) to have their wisdom teeth removed. After surgery, the patients first evaluated their pain as the origin alan-aesthesia wore off, and then every 20 minutes after they were given a shot of a kappa-opioid. The link between sex and the effectiveness of the drugs was clear, the researchers report in this month’s issue of Nature Medicine. Although the women reported a higher level of pain shortly after surgery, 20 minutes after a dose of the opioid their pain had lessened to a greater degree than it had for the men. And the women’ s pain relief continued for hours after the drug’ s effects began to wane in the men. "I’m very excited about this result," says Karen Berkey, a pain researcher at Florida State university in Tallahassee. In addition to sex differences, she would now like to see researchers explore other factors—such as age that might influence the effectiveness of painkillers. If scientists can understand why such differences exist, it may be possible to develop "designer" painkillers tailored (适应) to particular types of patient. Levine says the findings should prompt researchers to reexamine drugs abandoned as useless simply because they did not work in men-only trials. Whatever the outcome of the research, Levine says that a lot of the credit is due to the unknown reviewer who readjusted the focus of his work." Everyone in the group is appreciative," he says, "we’ re just sorry reviewing is done anonymously (匿名方式) and we couldn’t thank this person."According to Berkley, the effectiveness of painkillers______.

A．could be explored in men
B．is clearly linked with age
C．is mainly influenced by sexual differences
D．might not be only decided by sexual differences

单项选择题

Some problems can be readily identified simply by looking around. These problems concern the pollution of our environment by technology as a result of sudden upsets in the physical, economic and social balance. The most obvious of these are the general pollution of our physical environment and the destruction of irreplaceable natural resources. Not so obvious as these, but just as painfully significant to some, are the disappearing and changing of jobs which overnight often create large groups of jobless citizens. Can technology be used to undo what it has done, replace what it has destroyed or substitute for what it has caused to disappear No one knows. Many wonder whether or not all of the sources of pollution have yet been identified, whether or not they are being arrested and whether or not they will be prevented from recurring. Another set of problems relates to what technological advancement has done to the quality of life. An improved social life has not been unfortunately, either the goal or the chief beneficiary of technological change. Rather, any improvements that have occurred have been more accidental than intended. Too much has happened too fast. The changes demanded of marriage and family relationships remain largely unexamined. It is often a matter of "put up or shut up", and a person has to adapt his lifestyle to ever-changing conditions with little time for choice. The "no-move-no-advancement" type is an example of one such problem. Many people are coming to think that the reward is simply not worthy of the struggle, and they are taking jobs with less responsibility and lower pay.According to the passage, no one knows whether or not technology______.

A．will solve the problems it has created
B．will continue to produce conveniences
C．will stop advancing
D．will undo itself

单项选择题

Children are getting so fat they may be the first generation to die before their parents, an expert claimed yesterday. Today’s youngsters are already falling prey to potential killers such as diabetes because of their weight. Fatty fast-food diets combined with sedentary lifestyles dominated by televisions and computers could mean kids will die tragically young, says Professor Andrew Prentice, from the London School of Hygiene and Tropical Medicine. At the same time, the shape of the human body is going through a huge evolutionary shift because adults are getting so fat. Here in Britain, latest research shows that the average waist size for a man is 36 -38 in and may be 42 -44 in by 2032. This compares with only 32. 6 in 1972. Women’ s waists have grown from an average of 22 inches in 1920 to 24 inches in the Fifties and 30 inches now. One of the major reasons why children now are at greater risk is that we are getting fatter younger. In the UK alone, more than one million under 16s are classed as overweight or obese—double the number in the mid-Eighties. One in ten four-year-olds are also medically classified as obese. The obesity pandemic—an extensive epidemic—which started in the U. S. , has now spread to Europe, Australia, Central America and the Middle East. Many nations now record more than 20 percent of their population as clinically obese and well over half the population as overweight. Prof Prentice said the change in our shape has been caused by a glut of easily available high-energy foods combined with a dramatic drop in the energy we use as a result of technology developments. He is not alone in his concern. Only last week one medical journal revealed how obesity was fueling a rise in cancer cases. Obesity also increases the risk factor for strokes and heart disease. An averagely obese person’s lifespan is shortened by around nine years while a severely obese person by many more. Prof Prentice said: "So will parents outlive their children, as claimed recently by an American obesity specialist" The answer is yes—and no. Yes, when the offspring becomes grossly obese. This is now becoming an alarmingly common occurrence in the U. S.. Such children and adolescents have a greatly reduced quality of life in terms of both their physical and psychosocial health. So say No to that doughnut and burger.What does the word "sedentary ( Para. 1)" mean

A．Sit still.
B．Eat too much.
C．Study very hard.
D．Passive thinking.

单项选择题

Men and women may need to be treated differently when it comes to pain. Researchers in California have found that certain painkillers provide greater and longer-lasting relief for women than they do for men. This suggests that the physiology of pain differs between the sexes. The discovery could lead doctors to change the way they prescribe analgesic drugs. In controlled experiments, women often report higher levels of pain. But when it comes to prescribing and developing new analgesics, medical science usually ignores the sex of the patient, says Jon Levine, a specialist in inflammatory diseases at the University of California, San Francisco. Levine says that sexual differences were the last thing on his mind when his research group started studying a class of analgesics called kappa-opioids, which are chemical cousins to morphine and heroin. The researchers found that the drugs were less effective in controlling pain than their better-known kin(家属). But when they tried to publish their results, an expert reviewer spotted the fact that some of the treatment groups contained more women than men, and suggested that the researchers reanalyze the data to see if this accounted for their results. "To our surprise, all the effect could be ascribed to sex," says Levine. To test the effect of sex directly, Levine’s team recruited 20 men and 28 women who were due(预订) to have their wisdom teeth removed. After surgery, the patients first evaluated their pain as the origin alan-aesthesia wore off, and then every 20 minutes after they were given a shot of a kappa-opioid. The link between sex and the effectiveness of the drugs was clear, the researchers report in this month’s issue of Nature Medicine. Although the women reported a higher level of pain shortly after surgery, 20 minutes after a dose of the opioid their pain had lessened to a greater degree than it had for the men. And the women’ s pain relief continued for hours after the drug’ s effects began to wane in the men. "I’m very excited about this result," says Karen Berkey, a pain researcher at Florida State university in Tallahassee. In addition to sex differences, she would now like to see researchers explore other factors—such as age that might influence the effectiveness of painkillers. If scientists can understand why such differences exist, it may be possible to develop "designer" painkillers tailored (适应) to particular types of patient. Levine says the findings should prompt researchers to reexamine drugs abandoned as useless simply because they did not work in men-only trials. Whatever the outcome of the research, Levine says that a lot of the credit is due to the unknown reviewer who readjusted the focus of his work." Everyone in the group is appreciative," he says, "we’ re just sorry reviewing is done anonymously (匿名方式) and we couldn’t thank this person."As Levine implies, the drugs abandoned as useless______.

A．had been tailored to a particular type of patients
B．were not effective in different ages of groups
C．had not been developed properly
D．might work in women

单项选择题

Some problems can be readily identified simply by looking around. These problems concern the pollution of our environment by technology as a result of sudden upsets in the physical, economic and social balance. The most obvious of these are the general pollution of our physical environment and the destruction of irreplaceable natural resources. Not so obvious as these, but just as painfully significant to some, are the disappearing and changing of jobs which overnight often create large groups of jobless citizens. Can technology be used to undo what it has done, replace what it has destroyed or substitute for what it has caused to disappear No one knows. Many wonder whether or not all of the sources of pollution have yet been identified, whether or not they are being arrested and whether or not they will be prevented from recurring. Another set of problems relates to what technological advancement has done to the quality of life. An improved social life has not been unfortunately, either the goal or the chief beneficiary of technological change. Rather, any improvements that have occurred have been more accidental than intended. Too much has happened too fast. The changes demanded of marriage and family relationships remain largely unexamined. It is often a matter of "put up or shut up", and a person has to adapt his lifestyle to ever-changing conditions with little time for choice. The "no-move-no-advancement" type is an example of one such problem. Many people are coming to think that the reward is simply not worthy of the struggle, and they are taking jobs with less responsibility and lower pay.The author would say that technological advancement______.

A．has done nothing to the quality of life
B．has improved the quality of life
C．has harmed the quality of life
D．has redefined the quality of life

单项选择题

Children are getting so fat they may be the first generation to die before their parents, an expert claimed yesterday. Today’s youngsters are already falling prey to potential killers such as diabetes because of their weight. Fatty fast-food diets combined with sedentary lifestyles dominated by televisions and computers could mean kids will die tragically young, says Professor Andrew Prentice, from the London School of Hygiene and Tropical Medicine. At the same time, the shape of the human body is going through a huge evolutionary shift because adults are getting so fat. Here in Britain, latest research shows that the average waist size for a man is 36 -38 in and may be 42 -44 in by 2032. This compares with only 32. 6 in 1972. Women’ s waists have grown from an average of 22 inches in 1920 to 24 inches in the Fifties and 30 inches now. One of the major reasons why children now are at greater risk is that we are getting fatter younger. In the UK alone, more than one million under 16s are classed as overweight or obese—double the number in the mid-Eighties. One in ten four-year-olds are also medically classified as obese. The obesity pandemic—an extensive epidemic—which started in the U. S. , has now spread to Europe, Australia, Central America and the Middle East. Many nations now record more than 20 percent of their population as clinically obese and well over half the population as overweight. Prof Prentice said the change in our shape has been caused by a glut of easily available high-energy foods combined with a dramatic drop in the energy we use as a result of technology developments. He is not alone in his concern. Only last week one medical journal revealed how obesity was fueling a rise in cancer cases. Obesity also increases the risk factor for strokes and heart disease. An averagely obese person’s lifespan is shortened by around nine years while a severely obese person by many more. Prof Prentice said: "So will parents outlive their children, as claimed recently by an American obesity specialist" The answer is yes—and no. Yes, when the offspring becomes grossly obese. This is now becoming an alarmingly common occurrence in the U. S.. Such children and adolescents have a greatly reduced quality of life in terms of both their physical and psychosocial health. So say No to that doughnut and burger.Which statement is TRUE

A．The average waist size for a man is 36-38 in.
B．The average waist size for a woman is 30 in.
C．In the mid-Eighties, more than half million under-16s in the UK are classed as overweight.
D．The obesity pandemic has now spread to South America.

单项选择题

Some problems can be readily identified simply by looking around. These problems concern the pollution of our environment by technology as a result of sudden upsets in the physical, economic and social balance. The most obvious of these are the general pollution of our physical environment and the destruction of irreplaceable natural resources. Not so obvious as these, but just as painfully significant to some, are the disappearing and changing of jobs which overnight often create large groups of jobless citizens. Can technology be used to undo what it has done, replace what it has destroyed or substitute for what it has caused to disappear No one knows. Many wonder whether or not all of the sources of pollution have yet been identified, whether or not they are being arrested and whether or not they will be prevented from recurring. Another set of problems relates to what technological advancement has done to the quality of life. An improved social life has not been unfortunately, either the goal or the chief beneficiary of technological change. Rather, any improvements that have occurred have been more accidental than intended. Too much has happened too fast. The changes demanded of marriage and family relationships remain largely unexamined. It is often a matter of "put up or shut up", and a person has to adapt his lifestyle to ever-changing conditions with little time for choice. The "no-move-no-advancement" type is an example of one such problem. Many people are coming to think that the reward is simply not worthy of the struggle, and they are taking jobs with less responsibility and lower pay.What do you learn from the phrase "put up or shut up" in the third paragraph

A．Technology has put a great deal of stress on people’s lives.
B．People can’t live with the stresses caused by technology.
C．People are quite active in dealing with the stresses caused by technology.
D．People are quite passive in dealing with the stresses caused by technology.

单项选择题

Children are getting so fat they may be the first generation to die before their parents, an expert claimed yesterday. Today’s youngsters are already falling prey to potential killers such as diabetes because of their weight. Fatty fast-food diets combined with sedentary lifestyles dominated by televisions and computers could mean kids will die tragically young, says Professor Andrew Prentice, from the London School of Hygiene and Tropical Medicine. At the same time, the shape of the human body is going through a huge evolutionary shift because adults are getting so fat. Here in Britain, latest research shows that the average waist size for a man is 36 -38 in and may be 42 -44 in by 2032. This compares with only 32. 6 in 1972. Women’ s waists have grown from an average of 22 inches in 1920 to 24 inches in the Fifties and 30 inches now. One of the major reasons why children now are at greater risk is that we are getting fatter younger. In the UK alone, more than one million under 16s are classed as overweight or obese—double the number in the mid-Eighties. One in ten four-year-olds are also medically classified as obese. The obesity pandemic—an extensive epidemic—which started in the U. S. , has now spread to Europe, Australia, Central America and the Middle East. Many nations now record more than 20 percent of their population as clinically obese and well over half the population as overweight. Prof Prentice said the change in our shape has been caused by a glut of easily available high-energy foods combined with a dramatic drop in the energy we use as a result of technology developments. He is not alone in his concern. Only last week one medical journal revealed how obesity was fueling a rise in cancer cases. Obesity also increases the risk factor for strokes and heart disease. An averagely obese person’s lifespan is shortened by around nine years while a severely obese person by many more. Prof Prentice said: "So will parents outlive their children, as claimed recently by an American obesity specialist" The answer is yes—and no. Yes, when the offspring becomes grossly obese. This is now becoming an alarmingly common occurrence in the U. S.. Such children and adolescents have a greatly reduced quality of life in terms of both their physical and psychosocial health. So say No to that doughnut and burger.According to Prof Prentice, what are the reasons for the change in our shape

A．We eat too much and refuse to do physical exercises.
B．High-energy foods are easy to get and technology develops fast.
C．High-energy foods are the main diet and we use technology.
D．High-energy foods are easy to get and we consume less energy.

单项选择题

Some problems can be readily identified simply by looking around. These problems concern the pollution of our environment by technology as a result of sudden upsets in the physical, economic and social balance. The most obvious of these are the general pollution of our physical environment and the destruction of irreplaceable natural resources. Not so obvious as these, but just as painfully significant to some, are the disappearing and changing of jobs which overnight often create large groups of jobless citizens. Can technology be used to undo what it has done, replace what it has destroyed or substitute for what it has caused to disappear No one knows. Many wonder whether or not all of the sources of pollution have yet been identified, whether or not they are being arrested and whether or not they will be prevented from recurring. Another set of problems relates to what technological advancement has done to the quality of life. An improved social life has not been unfortunately, either the goal or the chief beneficiary of technological change. Rather, any improvements that have occurred have been more accidental than intended. Too much has happened too fast. The changes demanded of marriage and family relationships remain largely unexamined. It is often a matter of "put up or shut up", and a person has to adapt his lifestyle to ever-changing conditions with little time for choice. The "no-move-no-advancement" type is an example of one such problem. Many people are coming to think that the reward is simply not worthy of the struggle, and they are taking jobs with less responsibility and lower pay.It can be concluded from the third paragraph that technological advancement has resulted in quick living pace which______.

A．is harmful to society
B．is socially rewarding
C．leads to further improvements
D．characterizes modern society

单项选择题

Children are getting so fat they may be the first generation to die before their parents, an expert claimed yesterday. Today’s youngsters are already falling prey to potential killers such as diabetes because of their weight. Fatty fast-food diets combined with sedentary lifestyles dominated by televisions and computers could mean kids will die tragically young, says Professor Andrew Prentice, from the London School of Hygiene and Tropical Medicine. At the same time, the shape of the human body is going through a huge evolutionary shift because adults are getting so fat. Here in Britain, latest research shows that the average waist size for a man is 36 -38 in and may be 42 -44 in by 2032. This compares with only 32. 6 in 1972. Women’ s waists have grown from an average of 22 inches in 1920 to 24 inches in the Fifties and 30 inches now. One of the major reasons why children now are at greater risk is that we are getting fatter younger. In the UK alone, more than one million under 16s are classed as overweight or obese—double the number in the mid-Eighties. One in ten four-year-olds are also medically classified as obese. The obesity pandemic—an extensive epidemic—which started in the U. S. , has now spread to Europe, Australia, Central America and the Middle East. Many nations now record more than 20 percent of their population as clinically obese and well over half the population as overweight. Prof Prentice said the change in our shape has been caused by a glut of easily available high-energy foods combined with a dramatic drop in the energy we use as a result of technology developments. He is not alone in his concern. Only last week one medical journal revealed how obesity was fueling a rise in cancer cases. Obesity also increases the risk factor for strokes and heart disease. An averagely obese person’s lifespan is shortened by around nine years while a severely obese person by many more. Prof Prentice said: "So will parents outlive their children, as claimed recently by an American obesity specialist" The answer is yes—and no. Yes, when the offspring becomes grossly obese. This is now becoming an alarmingly common occurrence in the U. S.. Such children and adolescents have a greatly reduced quality of life in terms of both their physical and psychosocial health. So say No to that doughnut and burger.Obesity increases the risk factor of______.

A．diabetes, short sight, cancer, strokes
B．diabetes, cancer, strokes, psychosocial illness
C．cancer, strokes, fatty, heart disease
D．strokes, heart disease, diabetes, headache

单项选择题

Children are getting so fat they may be the first generation to die before their parents, an expert claimed yesterday. Today’s youngsters are already falling prey to potential killers such as diabetes because of their weight. Fatty fast-food diets combined with sedentary lifestyles dominated by televisions and computers could mean kids will die tragically young, says Professor Andrew Prentice, from the London School of Hygiene and Tropical Medicine. At the same time, the shape of the human body is going through a huge evolutionary shift because adults are getting so fat. Here in Britain, latest research shows that the average waist size for a man is 36 -38 in and may be 42 -44 in by 2032. This compares with only 32. 6 in 1972. Women’ s waists have grown from an average of 22 inches in 1920 to 24 inches in the Fifties and 30 inches now. One of the major reasons why children now are at greater risk is that we are getting fatter younger. In the UK alone, more than one million under 16s are classed as overweight or obese—double the number in the mid-Eighties. One in ten four-year-olds are also medically classified as obese. The obesity pandemic—an extensive epidemic—which started in the U. S. , has now spread to Europe, Australia, Central America and the Middle East. Many nations now record more than 20 percent of their population as clinically obese and well over half the population as overweight. Prof Prentice said the change in our shape has been caused by a glut of easily available high-energy foods combined with a dramatic drop in the energy we use as a result of technology developments. He is not alone in his concern. Only last week one medical journal revealed how obesity was fueling a rise in cancer cases. Obesity also increases the risk factor for strokes and heart disease. An averagely obese person’s lifespan is shortened by around nine years while a severely obese person by many more. Prof Prentice said: "So will parents outlive their children, as claimed recently by an American obesity specialist" The answer is yes—and no. Yes, when the offspring becomes grossly obese. This is now becoming an alarmingly common occurrence in the U. S.. Such children and adolescents have a greatly reduced quality of life in terms of both their physical and psychosocial health. So say No to that doughnut and burger.What does the author mean by "So say No to that doughnut and burger"

A．Answering the question "will parents outlive their children".
B．The doughnut and burger should be banned.
C．We should lead a healthy life.
D．We should begin dieting.

单项选择题

While traveling for various speaking engagements, I frequently stay overnight in the home of a family and am invited to one of the children’s bedrooms. In it, I often find so many playthings that there’s almost no room. And the closet is usually so tightly packed with clothes that I can barely squeeze in my jacket. I’ m not complaining, only making a point. I think that the tendency to give children an overabundance (过多) of toys and clothes is quite common in American families, and I think that in far too many families not only do children come to take their parents’ generosity for granted, but also the effects of this can actually be somewhat harmful to children. Of course, I’ m not only thinking of the material possessions children are given. Children can also be overindulged (过分宠爱) with too many privileges—for example, when parents send a child to an expensive summer camp that the parents can’t really afford. Why One fairly common reason is that parents overindulge their children out of a sense of guilt. Parents who both hold down full-time jobs may feel guilty about the amount of time they spend away from their children and may attempt to compensate by showering them with material possessions. Overindulgence of a child also happens when parents are unable to stand up to their children’s unreasonable demands. Such parents vacillate between saying no and giving in—but neither response seems satisfactory to them. If they refuse a request, they immediately feel a wave of remorse for having been so strict or ungenerous. If they give in, they feel regret and resentment over having been a pushover. This kind of vacillation not only impairs the parents’ ability to set limits, it also sours the parent-child relationship to some degree, robbing parents and their children of some of the happiness and mutual respect that should be present in healthy families. But overindulging children with material things does little to lessen parental guilt (since parents never feel that they’ve given enough), nor does it make children feel more loved (for what children really crave is parents’ time and attention). Instead, the effects of overindulgence can be harmful. Children may, to some degree become greedy, self-centered, ungrateful and insensitive to the needs and feelings of others, beginning with their parents. When children are given too much, their respect for their parents would be undermined.The writer uses the example of his staying overnight in other family’s home to______.

A．make a point that the American kids have many toys
B．complain the kids are given too much by their parents
C．illustrate the fact of overindulgence in America and its harmful result
D．prove the difficulty to squeeze in anything due to an overabundance of toys

单项选择题

Binge eating changes the way the body responds to Leptin(瘦素) , the key appetite-suppressing hormone, say researchers in New York. Their experiments with rats could explain why people who overeat continue to crave food despite ginning weight. As we eat, Leptin levels in our blood gradually rise and suppress the appetite until more energy is needed. Leptin also speeds up the metabolism, so that less food is converted to fat. "The object is to take you back to the original point," says Luciano Rossetti, a diabetes researcher at the Albert Einstein College of Medicine. But a popular theory holds that if Leptin worked too well, it would defeat the purpose of fat, which is to store energy for lean times. Animals that can build up fat reserves when meals abound have a better chance of survival than their skinny companions should famine strike. To understand how Leptin keeps fat in check without preventing it from accumulating vital reserves, Rossetti and his colleagues created feast and famine conditions for two groups of rats. Over three days, members of one group could eat all they wanted, while the other rats were kept on a restricted diet. Normally, Leptin moderates its own production slightly by reducing the activity of the Leptin gene in fat cells. In the rats with a skimpy diet, however, an injection of Leptin into the bloodstream hardly reduced the activity of the gene in fat tissue at all. By contrast, in the overeaters the injection cut Leptin gene activity in half. That came as a surprise, says Rossetti, as it means the overeaters would counteract an appetite-suppressing boost in Leptin, such as that caused by a meal, more quickly than the dieting rats. One possible outcome is that the guzzlers would be ready to eat again sooner. Similar mechanisms in humans may have given them an evolutionary advantage in prehistoric times, when food was probably scarce. But today it may lead to a spiral of overeating, Rossetti says, with each binge making a person more prone to the next: "People go on numerous circles of increased feeding." Since the tendency toward obesity varies from person to person, Rossetti plans to look for differences in the Leptin binge response in lean and fat strains of rats. Jeffrey Flier, a Leptin researcher at Beth Israel Hospital in Boston, says it would also be important to check whether moderately overweight people fail to increase the activity of their Leptin gene when they overeat. Without such experiments, he says, it’s hard to conclude that Rossetti has discovered why inflated waist lines are so common. "At this stage, it’s still purely hypothetical."Leptin functions______.

A．to restrain us from gaining weight
B．to regulate our metabolism
C．to suppress our appetite
D．all of the above

单项选择题

While traveling for various speaking engagements, I frequently stay overnight in the home of a family and am invited to one of the children’s bedrooms. In it, I often find so many playthings that there’s almost no room. And the closet is usually so tightly packed with clothes that I can barely squeeze in my jacket. I’ m not complaining, only making a point. I think that the tendency to give children an overabundance (过多) of toys and clothes is quite common in American families, and I think that in far too many families not only do children come to take their parents’ generosity for granted, but also the effects of this can actually be somewhat harmful to children. Of course, I’ m not only thinking of the material possessions children are given. Children can also be overindulged (过分宠爱) with too many privileges—for example, when parents send a child to an expensive summer camp that the parents can’t really afford. Why One fairly common reason is that parents overindulge their children out of a sense of guilt. Parents who both hold down full-time jobs may feel guilty about the amount of time they spend away from their children and may attempt to compensate by showering them with material possessions. Overindulgence of a child also happens when parents are unable to stand up to their children’s unreasonable demands. Such parents vacillate between saying no and giving in—but neither response seems satisfactory to them. If they refuse a request, they immediately feel a wave of remorse for having been so strict or ungenerous. If they give in, they feel regret and resentment over having been a pushover. This kind of vacillation not only impairs the parents’ ability to set limits, it also sours the parent-child relationship to some degree, robbing parents and their children of some of the happiness and mutual respect that should be present in healthy families. But overindulging children with material things does little to lessen parental guilt (since parents never feel that they’ve given enough), nor does it make children feel more loved (for what children really crave is parents’ time and attention). Instead, the effects of overindulgence can be harmful. Children may, to some degree become greedy, self-centered, ungrateful and insensitive to the needs and feelings of others, beginning with their parents. When children are given too much, their respect for their parents would be undermined.According to the text, the overindulgence of the children refers to the______.

A．overabundance of toys and clothes
B．generosity of the parents taken for granted
C．expensive gifts that parents cannot afford
D．excessive material possessions and privileges

单项选择题

Binge eating changes the way the body responds to Leptin(瘦素) , the key appetite-suppressing hormone, say researchers in New York. Their experiments with rats could explain why people who overeat continue to crave food despite ginning weight. As we eat, Leptin levels in our blood gradually rise and suppress the appetite until more energy is needed. Leptin also speeds up the metabolism, so that less food is converted to fat. "The object is to take you back to the original point," says Luciano Rossetti, a diabetes researcher at the Albert Einstein College of Medicine. But a popular theory holds that if Leptin worked too well, it would defeat the purpose of fat, which is to store energy for lean times. Animals that can build up fat reserves when meals abound have a better chance of survival than their skinny companions should famine strike. To understand how Leptin keeps fat in check without preventing it from accumulating vital reserves, Rossetti and his colleagues created feast and famine conditions for two groups of rats. Over three days, members of one group could eat all they wanted, while the other rats were kept on a restricted diet. Normally, Leptin moderates its own production slightly by reducing the activity of the Leptin gene in fat cells. In the rats with a skimpy diet, however, an injection of Leptin into the bloodstream hardly reduced the activity of the gene in fat tissue at all. By contrast, in the overeaters the injection cut Leptin gene activity in half. That came as a surprise, says Rossetti, as it means the overeaters would counteract an appetite-suppressing boost in Leptin, such as that caused by a meal, more quickly than the dieting rats. One possible outcome is that the guzzlers would be ready to eat again sooner. Similar mechanisms in humans may have given them an evolutionary advantage in prehistoric times, when food was probably scarce. But today it may lead to a spiral of overeating, Rossetti says, with each binge making a person more prone to the next: "People go on numerous circles of increased feeding." Since the tendency toward obesity varies from person to person, Rossetti plans to look for differences in the Leptin binge response in lean and fat strains of rats. Jeffrey Flier, a Leptin researcher at Beth Israel Hospital in Boston, says it would also be important to check whether moderately overweight people fail to increase the activity of their Leptin gene when they overeat. Without such experiments, he says, it’s hard to conclude that Rossetti has discovered why inflated waist lines are so common. "At this stage, it’s still purely hypothetical."The original function of Leptin, according to the passage______.

A．can be maintained intact
B．can be regulated at will
C．can be suppressed
D．can be distorted

单项选择题

While traveling for various speaking engagements, I frequently stay overnight in the home of a family and am invited to one of the children’s bedrooms. In it, I often find so many playthings that there’s almost no room. And the closet is usually so tightly packed with clothes that I can barely squeeze in my jacket. I’ m not complaining, only making a point. I think that the tendency to give children an overabundance (过多) of toys and clothes is quite common in American families, and I think that in far too many families not only do children come to take their parents’ generosity for granted, but also the effects of this can actually be somewhat harmful to children. Of course, I’ m not only thinking of the material possessions children are given. Children can also be overindulged (过分宠爱) with too many privileges—for example, when parents send a child to an expensive summer camp that the parents can’t really afford. Why One fairly common reason is that parents overindulge their children out of a sense of guilt. Parents who both hold down full-time jobs may feel guilty about the amount of time they spend away from their children and may attempt to compensate by showering them with material possessions. Overindulgence of a child also happens when parents are unable to stand up to their children’s unreasonable demands. Such parents vacillate between saying no and giving in—but neither response seems satisfactory to them. If they refuse a request, they immediately feel a wave of remorse for having been so strict or ungenerous. If they give in, they feel regret and resentment over having been a pushover. This kind of vacillation not only impairs the parents’ ability to set limits, it also sours the parent-child relationship to some degree, robbing parents and their children of some of the happiness and mutual respect that should be present in healthy families. But overindulging children with material things does little to lessen parental guilt (since parents never feel that they’ve given enough), nor does it make children feel more loved (for what children really crave is parents’ time and attention). Instead, the effects of overindulgence can be harmful. Children may, to some degree become greedy, self-centered, ungrateful and insensitive to the needs and feelings of others, beginning with their parents. When children are given too much, their respect for their parents would be undermined.Parents overindulge their children out of a sense of guilt because the parents______.

A．cannot earn enough money to show children with material possession
B．use the material things to make up for the shortage of time with children
C．cannot stand up to their children’s unreasonable demands
D．vacillate between feeling guilty and being too strict

单项选择题

Binge eating changes the way the body responds to Leptin(瘦素) , the key appetite-suppressing hormone, say researchers in New York. Their experiments with rats could explain why people who overeat continue to crave food despite ginning weight. As we eat, Leptin levels in our blood gradually rise and suppress the appetite until more energy is needed. Leptin also speeds up the metabolism, so that less food is converted to fat. "The object is to take you back to the original point," says Luciano Rossetti, a diabetes researcher at the Albert Einstein College of Medicine. But a popular theory holds that if Leptin worked too well, it would defeat the purpose of fat, which is to store energy for lean times. Animals that can build up fat reserves when meals abound have a better chance of survival than their skinny companions should famine strike. To understand how Leptin keeps fat in check without preventing it from accumulating vital reserves, Rossetti and his colleagues created feast and famine conditions for two groups of rats. Over three days, members of one group could eat all they wanted, while the other rats were kept on a restricted diet. Normally, Leptin moderates its own production slightly by reducing the activity of the Leptin gene in fat cells. In the rats with a skimpy diet, however, an injection of Leptin into the bloodstream hardly reduced the activity of the gene in fat tissue at all. By contrast, in the overeaters the injection cut Leptin gene activity in half. That came as a surprise, says Rossetti, as it means the overeaters would counteract an appetite-suppressing boost in Leptin, such as that caused by a meal, more quickly than the dieting rats. One possible outcome is that the guzzlers would be ready to eat again sooner. Similar mechanisms in humans may have given them an evolutionary advantage in prehistoric times, when food was probably scarce. But today it may lead to a spiral of overeating, Rossetti says, with each binge making a person more prone to the next: "People go on numerous circles of increased feeding." Since the tendency toward obesity varies from person to person, Rossetti plans to look for differences in the Leptin binge response in lean and fat strains of rats. Jeffrey Flier, a Leptin researcher at Beth Israel Hospital in Boston, says it would also be important to check whether moderately overweight people fail to increase the activity of their Leptin gene when they overeat. Without such experiments, he says, it’s hard to conclude that Rossetti has discovered why inflated waist lines are so common. "At this stage, it’s still purely hypothetical."It is hypothetical that the rats fed on a bumper diet______.

A．can boost their appetite by increasing the activity of Leptin gene in fat cells
B．can counteract their biological evolution
C．can inhibit their mechanism responsible for quelling appetite
D．can slow the production of Leptin

单项选择题

While traveling for various speaking engagements, I frequently stay overnight in the home of a family and am invited to one of the children’s bedrooms. In it, I often find so many playthings that there’s almost no room. And the closet is usually so tightly packed with clothes that I can barely squeeze in my jacket. I’ m not complaining, only making a point. I think that the tendency to give children an overabundance (过多) of toys and clothes is quite common in American families, and I think that in far too many families not only do children come to take their parents’ generosity for granted, but also the effects of this can actually be somewhat harmful to children. Of course, I’ m not only thinking of the material possessions children are given. Children can also be overindulged (过分宠爱) with too many privileges—for example, when parents send a child to an expensive summer camp that the parents can’t really afford. Why One fairly common reason is that parents overindulge their children out of a sense of guilt. Parents who both hold down full-time jobs may feel guilty about the amount of time they spend away from their children and may attempt to compensate by showering them with material possessions. Overindulgence of a child also happens when parents are unable to stand up to their children’s unreasonable demands. Such parents vacillate between saying no and giving in—but neither response seems satisfactory to them. If they refuse a request, they immediately feel a wave of remorse for having been so strict or ungenerous. If they give in, they feel regret and resentment over having been a pushover. This kind of vacillation not only impairs the parents’ ability to set limits, it also sours the parent-child relationship to some degree, robbing parents and their children of some of the happiness and mutual respect that should be present in healthy families. But overindulging children with material things does little to lessen parental guilt (since parents never feel that they’ve given enough), nor does it make children feel more loved (for what children really crave is parents’ time and attention). Instead, the effects of overindulgence can be harmful. Children may, to some degree become greedy, self-centered, ungrateful and insensitive to the needs and feelings of others, beginning with their parents. When children are given too much, their respect for their parents would be undermined.Which of the following best defines the word "resentment" ( Line 4, Para. 5)

A．Reset.
B．Resistance.
C．Bitterness.
D．Hurt.

单项选择题

The bird flu virus is mutating and becoming more dangerous to mammals, according to researchers. The discovery reinforces fears that a human pandemic of the disease could yet occur. Avian flu hit the headlines in 1997 when a strain called H5N1 jumped from chickens to people, killing 6 people in Hong Kong. Within 3 days, the country’s entire chicken population was slaughtered and the outbreak was controlled. Since then new strains of virus have emerged, killing a further 14 people. As yet, no strain has been able to jump routinely from person to person. But if a more virulent strain evolves, the fear is that it could trigger widespread outbreaks, potentially affecting millions of people. Now, genetic and animal studies show that the virus is becoming more menacing to mammals. Immediate action is needed to stem the virus’s transmission, says Hualan Chen from Harbin Veterinary Research Institute, China, who was involved in the research. Chen and colleagues studied 21 H5N1 flu virus samples taken from apparently healthy ducks, which act as a natural reservoir for the disease, in southern China between 1999 and 2002. The researchers inoculated groups of chickens, mice and ducks with virus samples taken from different years and waited to see which animals became ill. Their results are presented this week in the Proceedings of the National Academy of Sciences. As expected, ducks were immune to the virus’s effects and the chickens fell sick. However, the mice also became ill, losing weight and the use of their limbs. Crucially, the severity of their illness was linked with the year from which the virus sample was taken. Viruses isolated in 2001 and 2002 made the animals more ill than those isolated earlier on. The findings hint that some time around 2001, the virus became adept at infecting mammals. Genetic analysis of the same samples reveals that the virus’s DNA changed over that time, suggesting that accumulated mutations may have contributed to the increased virulence. Researchers are concerned that a virus that has acquired the ability to infect mice could also infect humans. "The disease could resurge at any time," warns virologist Marion Koopmans from the National Institute of Public Health and the Environment in Bilthoven, the Netherlands. The findings highlight the need for improved surveillance to ensure that any future outbreaks are curtailed, she says. Although domestic poultry is easily culled, wild animals are more difficult to contain. " It is impossible to eradicate the natural reservoir," says Koopmans, "So we need to learn to live with it." Birds may not be the only villains in this story, however. Chen believes that pigs may also play a part. In Asia, chickens and pigs are often kept in close proximity, so the virus may have shuffled back and forth between the 2 species, picking up mutations and becoming better at infecting mammalian hosts. Humans may then have caught the disease from swine.This passage is mainly concerned with______.

A．the spread of the bird flu virus to mammals
B．the domestic and wild poultry population
C．H5N1 isolated only from chicken
D．a new virus strain jumping routinely from person to person

单项选择题

Binge eating changes the way the body responds to Leptin(瘦素) , the key appetite-suppressing hormone, say researchers in New York. Their experiments with rats could explain why people who overeat continue to crave food despite ginning weight. As we eat, Leptin levels in our blood gradually rise and suppress the appetite until more energy is needed. Leptin also speeds up the metabolism, so that less food is converted to fat. "The object is to take you back to the original point," says Luciano Rossetti, a diabetes researcher at the Albert Einstein College of Medicine. But a popular theory holds that if Leptin worked too well, it would defeat the purpose of fat, which is to store energy for lean times. Animals that can build up fat reserves when meals abound have a better chance of survival than their skinny companions should famine strike. To understand how Leptin keeps fat in check without preventing it from accumulating vital reserves, Rossetti and his colleagues created feast and famine conditions for two groups of rats. Over three days, members of one group could eat all they wanted, while the other rats were kept on a restricted diet. Normally, Leptin moderates its own production slightly by reducing the activity of the Leptin gene in fat cells. In the rats with a skimpy diet, however, an injection of Leptin into the bloodstream hardly reduced the activity of the gene in fat tissue at all. By contrast, in the overeaters the injection cut Leptin gene activity in half. That came as a surprise, says Rossetti, as it means the overeaters would counteract an appetite-suppressing boost in Leptin, such as that caused by a meal, more quickly than the dieting rats. One possible outcome is that the guzzlers would be ready to eat again sooner. Similar mechanisms in humans may have given them an evolutionary advantage in prehistoric times, when food was probably scarce. But today it may lead to a spiral of overeating, Rossetti says, with each binge making a person more prone to the next: "People go on numerous circles of increased feeding." Since the tendency toward obesity varies from person to person, Rossetti plans to look for differences in the Leptin binge response in lean and fat strains of rats. Jeffrey Flier, a Leptin researcher at Beth Israel Hospital in Boston, says it would also be important to check whether moderately overweight people fail to increase the activity of their Leptin gene when they overeat. Without such experiments, he says, it’s hard to conclude that Rossetti has discovered why inflated waist lines are so common. "At this stage, it’s still purely hypothetical."Rossetti would say that the similar mechanism in humans can trap overeaters in vicious spiral of excess______.

A．unless they can accumulate reserve in their bodies
B．so that they eat better than before
C．where there is a scarcity of food
D．when food is plenty

单项选择题

While traveling for various speaking engagements, I frequently stay overnight in the home of a family and am invited to one of the children’s bedrooms. In it, I often find so many playthings that there’s almost no room. And the closet is usually so tightly packed with clothes that I can barely squeeze in my jacket. I’ m not complaining, only making a point. I think that the tendency to give children an overabundance (过多) of toys and clothes is quite common in American families, and I think that in far too many families not only do children come to take their parents’ generosity for granted, but also the effects of this can actually be somewhat harmful to children. Of course, I’ m not only thinking of the material possessions children are given. Children can also be overindulged (过分宠爱) with too many privileges—for example, when parents send a child to an expensive summer camp that the parents can’t really afford. Why One fairly common reason is that parents overindulge their children out of a sense of guilt. Parents who both hold down full-time jobs may feel guilty about the amount of time they spend away from their children and may attempt to compensate by showering them with material possessions. Overindulgence of a child also happens when parents are unable to stand up to their children’s unreasonable demands. Such parents vacillate between saying no and giving in—but neither response seems satisfactory to them. If they refuse a request, they immediately feel a wave of remorse for having been so strict or ungenerous. If they give in, they feel regret and resentment over having been a pushover. This kind of vacillation not only impairs the parents’ ability to set limits, it also sours the parent-child relationship to some degree, robbing parents and their children of some of the happiness and mutual respect that should be present in healthy families. But overindulging children with material things does little to lessen parental guilt (since parents never feel that they’ve given enough), nor does it make children feel more loved (for what children really crave is parents’ time and attention). Instead, the effects of overindulgence can be harmful. Children may, to some degree become greedy, self-centered, ungrateful and insensitive to the needs and feelings of others, beginning with their parents. When children are given too much, their respect for their parents would be undermined.From the text, we can conclude that overindulging children may______.

A．lessen parental guilt but cannot make children feel more loved
B．make children greedy and not crave for parents’ attention and love
C．let parents feel less regretful for not having been so strict or ungenerous
D．result in children’s inconsideration of the others, starting from their parents

单项选择题

Binge eating changes the way the body responds to Leptin(瘦素) , the key appetite-suppressing hormone, say researchers in New York. Their experiments with rats could explain why people who overeat continue to crave food despite ginning weight. As we eat, Leptin levels in our blood gradually rise and suppress the appetite until more energy is needed. Leptin also speeds up the metabolism, so that less food is converted to fat. "The object is to take you back to the original point," says Luciano Rossetti, a diabetes researcher at the Albert Einstein College of Medicine. But a popular theory holds that if Leptin worked too well, it would defeat the purpose of fat, which is to store energy for lean times. Animals that can build up fat reserves when meals abound have a better chance of survival than their skinny companions should famine strike. To understand how Leptin keeps fat in check without preventing it from accumulating vital reserves, Rossetti and his colleagues created feast and famine conditions for two groups of rats. Over three days, members of one group could eat all they wanted, while the other rats were kept on a restricted diet. Normally, Leptin moderates its own production slightly by reducing the activity of the Leptin gene in fat cells. In the rats with a skimpy diet, however, an injection of Leptin into the bloodstream hardly reduced the activity of the gene in fat tissue at all. By contrast, in the overeaters the injection cut Leptin gene activity in half. That came as a surprise, says Rossetti, as it means the overeaters would counteract an appetite-suppressing boost in Leptin, such as that caused by a meal, more quickly than the dieting rats. One possible outcome is that the guzzlers would be ready to eat again sooner. Similar mechanisms in humans may have given them an evolutionary advantage in prehistoric times, when food was probably scarce. But today it may lead to a spiral of overeating, Rossetti says, with each binge making a person more prone to the next: "People go on numerous circles of increased feeding." Since the tendency toward obesity varies from person to person, Rossetti plans to look for differences in the Leptin binge response in lean and fat strains of rats. Jeffrey Flier, a Leptin researcher at Beth Israel Hospital in Boston, says it would also be important to check whether moderately overweight people fail to increase the activity of their Leptin gene when they overeat. Without such experiments, he says, it’s hard to conclude that Rossetti has discovered why inflated waist lines are so common. "At this stage, it’s still purely hypothetical."The passage tells us that Flier argues that Rossetti’s findings______.

A．were convincing enough to be duplicated among moderately overweight people
B．cannot be repeated among moderately overweight people
C．merit further investigation
D．were fabricated

单项选择题

The bird flu virus is mutating and becoming more dangerous to mammals, according to researchers. The discovery reinforces fears that a human pandemic of the disease could yet occur. Avian flu hit the headlines in 1997 when a strain called H5N1 jumped from chickens to people, killing 6 people in Hong Kong. Within 3 days, the country’s entire chicken population was slaughtered and the outbreak was controlled. Since then new strains of virus have emerged, killing a further 14 people. As yet, no strain has been able to jump routinely from person to person. But if a more virulent strain evolves, the fear is that it could trigger widespread outbreaks, potentially affecting millions of people. Now, genetic and animal studies show that the virus is becoming more menacing to mammals. Immediate action is needed to stem the virus’s transmission, says Hualan Chen from Harbin Veterinary Research Institute, China, who was involved in the research. Chen and colleagues studied 21 H5N1 flu virus samples taken from apparently healthy ducks, which act as a natural reservoir for the disease, in southern China between 1999 and 2002. The researchers inoculated groups of chickens, mice and ducks with virus samples taken from different years and waited to see which animals became ill. Their results are presented this week in the Proceedings of the National Academy of Sciences. As expected, ducks were immune to the virus’s effects and the chickens fell sick. However, the mice also became ill, losing weight and the use of their limbs. Crucially, the severity of their illness was linked with the year from which the virus sample was taken. Viruses isolated in 2001 and 2002 made the animals more ill than those isolated earlier on. The findings hint that some time around 2001, the virus became adept at infecting mammals. Genetic analysis of the same samples reveals that the virus’s DNA changed over that time, suggesting that accumulated mutations may have contributed to the increased virulence. Researchers are concerned that a virus that has acquired the ability to infect mice could also infect humans. "The disease could resurge at any time," warns virologist Marion Koopmans from the National Institute of Public Health and the Environment in Bilthoven, the Netherlands. The findings highlight the need for improved surveillance to ensure that any future outbreaks are curtailed, she says. Although domestic poultry is easily culled, wild animals are more difficult to contain. " It is impossible to eradicate the natural reservoir," says Koopmans, "So we need to learn to live with it." Birds may not be the only villains in this story, however. Chen believes that pigs may also play a part. In Asia, chickens and pigs are often kept in close proximity, so the virus may have shuffled back and forth between the 2 species, picking up mutations and becoming better at infecting mammalian hosts. Humans may then have caught the disease from swine.The fact that the H5N1 virus was isolated from apparently healthy ducks suggests that ______.

A．researchers worked really hard
B．ducks were inoculated with H5N1 vaccine
C．ducks might be a natural host of the virus
D．the virus made animals sicker than other viruses

单项选择题

The bird flu virus is mutating and becoming more dangerous to mammals, according to researchers. The discovery reinforces fears that a human pandemic of the disease could yet occur. Avian flu hit the headlines in 1997 when a strain called H5N1 jumped from chickens to people, killing 6 people in Hong Kong. Within 3 days, the country’s entire chicken population was slaughtered and the outbreak was controlled. Since then new strains of virus have emerged, killing a further 14 people. As yet, no strain has been able to jump routinely from person to person. But if a more virulent strain evolves, the fear is that it could trigger widespread outbreaks, potentially affecting millions of people. Now, genetic and animal studies show that the virus is becoming more menacing to mammals. Immediate action is needed to stem the virus’s transmission, says Hualan Chen from Harbin Veterinary Research Institute, China, who was involved in the research. Chen and colleagues studied 21 H5N1 flu virus samples taken from apparently healthy ducks, which act as a natural reservoir for the disease, in southern China between 1999 and 2002. The researchers inoculated groups of chickens, mice and ducks with virus samples taken from different years and waited to see which animals became ill. Their results are presented this week in the Proceedings of the National Academy of Sciences. As expected, ducks were immune to the virus’s effects and the chickens fell sick. However, the mice also became ill, losing weight and the use of their limbs. Crucially, the severity of their illness was linked with the year from which the virus sample was taken. Viruses isolated in 2001 and 2002 made the animals more ill than those isolated earlier on. The findings hint that some time around 2001, the virus became adept at infecting mammals. Genetic analysis of the same samples reveals that the virus’s DNA changed over that time, suggesting that accumulated mutations may have contributed to the increased virulence. Researchers are concerned that a virus that has acquired the ability to infect mice could also infect humans. "The disease could resurge at any time," warns virologist Marion Koopmans from the National Institute of Public Health and the Environment in Bilthoven, the Netherlands. The findings highlight the need for improved surveillance to ensure that any future outbreaks are curtailed, she says. Although domestic poultry is easily culled, wild animals are more difficult to contain. " It is impossible to eradicate the natural reservoir," says Koopmans, "So we need to learn to live with it." Birds may not be the only villains in this story, however. Chen believes that pigs may also play a part. In Asia, chickens and pigs are often kept in close proximity, so the virus may have shuffled back and forth between the 2 species, picking up mutations and becoming better at infecting mammalian hosts. Humans may then have caught the disease from swine.We can infer from Paragraph 3 that______.

A．the year in which the virus was isolated has nothing to do with the severity of illness
B．ducks are more likely to contract avian flu
C．accumulated mutations have occurred in the H5N1 virus
D．mice that are immune to the virus become sick

单项选择题

The bird flu virus is mutating and becoming more dangerous to mammals, according to researchers. The discovery reinforces fears that a human pandemic of the disease could yet occur. Avian flu hit the headlines in 1997 when a strain called H5N1 jumped from chickens to people, killing 6 people in Hong Kong. Within 3 days, the country’s entire chicken population was slaughtered and the outbreak was controlled. Since then new strains of virus have emerged, killing a further 14 people. As yet, no strain has been able to jump routinely from person to person. But if a more virulent strain evolves, the fear is that it could trigger widespread outbreaks, potentially affecting millions of people. Now, genetic and animal studies show that the virus is becoming more menacing to mammals. Immediate action is needed to stem the virus’s transmission, says Hualan Chen from Harbin Veterinary Research Institute, China, who was involved in the research. Chen and colleagues studied 21 H5N1 flu virus samples taken from apparently healthy ducks, which act as a natural reservoir for the disease, in southern China between 1999 and 2002. The researchers inoculated groups of chickens, mice and ducks with virus samples taken from different years and waited to see which animals became ill. Their results are presented this week in the Proceedings of the National Academy of Sciences. As expected, ducks were immune to the virus’s effects and the chickens fell sick. However, the mice also became ill, losing weight and the use of their limbs. Crucially, the severity of their illness was linked with the year from which the virus sample was taken. Viruses isolated in 2001 and 2002 made the animals more ill than those isolated earlier on. The findings hint that some time around 2001, the virus became adept at infecting mammals. Genetic analysis of the same samples reveals that the virus’s DNA changed over that time, suggesting that accumulated mutations may have contributed to the increased virulence. Researchers are concerned that a virus that has acquired the ability to infect mice could also infect humans. "The disease could resurge at any time," warns virologist Marion Koopmans from the National Institute of Public Health and the Environment in Bilthoven, the Netherlands. The findings highlight the need for improved surveillance to ensure that any future outbreaks are curtailed, she says. Although domestic poultry is easily culled, wild animals are more difficult to contain. " It is impossible to eradicate the natural reservoir," says Koopmans, "So we need to learn to live with it." Birds may not be the only villains in this story, however. Chen believes that pigs may also play a part. In Asia, chickens and pigs are often kept in close proximity, so the virus may have shuffled back and forth between the 2 species, picking up mutations and becoming better at infecting mammalian hosts. Humans may then have caught the disease from swine.The findings show that the accumulated mutations______.

A．have been adept at infecting mammals
B．may have contributed to the increased virulence of the virus
C．have led to the virus’ s DNA changes
D．require genetic analysis of the same samples

单项选择题

The bird flu virus is mutating and becoming more dangerous to mammals, according to researchers. The discovery reinforces fears that a human pandemic of the disease could yet occur. Avian flu hit the headlines in 1997 when a strain called H5N1 jumped from chickens to people, killing 6 people in Hong Kong. Within 3 days, the country’s entire chicken population was slaughtered and the outbreak was controlled. Since then new strains of virus have emerged, killing a further 14 people. As yet, no strain has been able to jump routinely from person to person. But if a more virulent strain evolves, the fear is that it could trigger widespread outbreaks, potentially affecting millions of people. Now, genetic and animal studies show that the virus is becoming more menacing to mammals. Immediate action is needed to stem the virus’s transmission, says Hualan Chen from Harbin Veterinary Research Institute, China, who was involved in the research. Chen and colleagues studied 21 H5N1 flu virus samples taken from apparently healthy ducks, which act as a natural reservoir for the disease, in southern China between 1999 and 2002. The researchers inoculated groups of chickens, mice and ducks with virus samples taken from different years and waited to see which animals became ill. Their results are presented this week in the Proceedings of the National Academy of Sciences. As expected, ducks were immune to the virus’s effects and the chickens fell sick. However, the mice also became ill, losing weight and the use of their limbs. Crucially, the severity of their illness was linked with the year from which the virus sample was taken. Viruses isolated in 2001 and 2002 made the animals more ill than those isolated earlier on. The findings hint that some time around 2001, the virus became adept at infecting mammals. Genetic analysis of the same samples reveals that the virus’s DNA changed over that time, suggesting that accumulated mutations may have contributed to the increased virulence. Researchers are concerned that a virus that has acquired the ability to infect mice could also infect humans. "The disease could resurge at any time," warns virologist Marion Koopmans from the National Institute of Public Health and the Environment in Bilthoven, the Netherlands. The findings highlight the need for improved surveillance to ensure that any future outbreaks are curtailed, she says. Although domestic poultry is easily culled, wild animals are more difficult to contain. " It is impossible to eradicate the natural reservoir," says Koopmans, "So we need to learn to live with it." Birds may not be the only villains in this story, however. Chen believes that pigs may also play a part. In Asia, chickens and pigs are often kept in close proximity, so the virus may have shuffled back and forth between the 2 species, picking up mutations and becoming better at infecting mammalian hosts. Humans may then have caught the disease from swine.Koopman is convinced that human beings must learn to live with bird flu because______.

A．study findings highlight the need for improved surveillance
B．wild animals are easy to cull
C．the disease could come back at any time
D．it is impossible to eliminate any natural host of the virus

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