According to the passage, a tiger’s te...

By 1970, according to a World Wildlife Fund report, only about 4,500 tigers survived throughout the world— half of them in India. Mr. Foresters, who followed and counted tiger footprints, estimated that in May 1972 only about 1,800 tiger existed in India. Project Tiger supported by W. W. F. was immediately launched. Nine tiger reserves were created, with armed guards protecting them. The project provided opportunities for researchers from India and abroad to study tigers in the reserves and gather previously unavailable information about their habits. Studies show that a male tiger may control a hunting territory of between 10 and 20 sq. kms. depending on its age, size and strength. The territory of a male includes the smaller territories of three or four tigresses. A tiger marks the boundaries of its territory by spraying urine (尿) and other bodily liquids on bushes. But it tries to avoid territorial fights, being guided by the distinctive body smell of other tigers. Tigers fight to death only when a tigress is defending her young, or when a tiger is guarding a tigress from the attentions of other males. The popular image of the tiger is that of a merciless and unconquerable hunter. But studies show that it catches only one of 20 victims it tries to attack. Fears have recently developed that Project Tiger has been too successful. It has enabled the tiger population to double (by mid-80s) but India’s human population has also grown out of control. Currently it is 750 million and likely to be 900 million by the end of the century. Land problem is becoming serious and many rural people feel bitter about the fact that some rich forests are reserved for tigers. A growing number of attacks by tigers on man has added to the hostility.The ultimate aim of Project Tiger is to________.

A．protect tigers from being killed
B．study the growth rate of tigers
C．promote the breeding of young tigers
D．analyze the behavioral patterns of tigers

单项选择题

By 1970, according to a World Wildlife Fund report, only about 4,500 tigers survived throughout the world— half of them in India. Mr. Foresters, who followed and counted tiger footprints, estimated that in May 1972 only about 1,800 tiger existed in India. Project Tiger supported by W. W. F. was immediately launched. Nine tiger reserves were created, with armed guards protecting them. The project provided opportunities for researchers from India and abroad to study tigers in the reserves and gather previously unavailable information about their habits. Studies show that a male tiger may control a hunting territory of between 10 and 20 sq. kms. depending on its age, size and strength. The territory of a male includes the smaller territories of three or four tigresses. A tiger marks the boundaries of its territory by spraying urine (尿) and other bodily liquids on bushes. But it tries to avoid territorial fights, being guided by the distinctive body smell of other tigers. Tigers fight to death only when a tigress is defending her young, or when a tiger is guarding a tigress from the attentions of other males. The popular image of the tiger is that of a merciless and unconquerable hunter. But studies show that it catches only one of 20 victims it tries to attack. Fears have recently developed that Project Tiger has been too successful. It has enabled the tiger population to double (by mid-80s) but India’s human population has also grown out of control. Currently it is 750 million and likely to be 900 million by the end of the century. Land problem is becoming serious and many rural people feel bitter about the fact that some rich forests are reserved for tigers. A growing number of attacks by tigers on man has added to the hostility.Studies have shown that________.

A．a tigress never attacks until attacked
B．the tigress is not as fierce as the tiger
C．the tiger is not an efficient hunter as is commonly described
D．a tiger usually fights another tiger to defend its own territory

单项选择题

We use both words and gestures to express our feelings, but the problem is that these words and gestures can be understood in different ways. It is true that a smile means the same thing in any language. So does laughter or crying. There are also a number of striking similarities in the way different animals show the same feelings. Dogs, tigers and humans, for example, often show their teeth when they are angry. This is probably because they are born with those behavior patterns. Fear is another emotion that is shown in much the same way all over the world. In Chinese and in English literature, a phrase like "he went pale and begin to tremble" suggests that the man is either very afraid or he has just got a very big shock. However, "he opened his eyes wide" is used to suggest anger in Chinese whereas in English it means surprise. In Chinese "surprise" can be described in a phrase like "they stretched out their tongues!" Sticking out your tongue in English is an insulting gesture or expresses strong dislike. Even in the same culture, people differ in ability to understand and express feelings. Experiments in America have shown that women are usually better than men at recognizing fear, anger, love and happiness on people’s faces. Other studies show that older people usually find it easier to recognize or understand body language than younger people do.According to the passage, ________.

A．we can hardly understand what people’s gestures mean
B．we can not often be sure what people mean when they describe their feelings in words or gestures
C．words can be better understood by older people
D．gestures can be understood by most of the people while words can not

单项选择题

By 1970, according to a World Wildlife Fund report, only about 4,500 tigers survived throughout the world— half of them in India. Mr. Foresters, who followed and counted tiger footprints, estimated that in May 1972 only about 1,800 tiger existed in India. Project Tiger supported by W. W. F. was immediately launched. Nine tiger reserves were created, with armed guards protecting them. The project provided opportunities for researchers from India and abroad to study tigers in the reserves and gather previously unavailable information about their habits. Studies show that a male tiger may control a hunting territory of between 10 and 20 sq. kms. depending on its age, size and strength. The territory of a male includes the smaller territories of three or four tigresses. A tiger marks the boundaries of its territory by spraying urine (尿) and other bodily liquids on bushes. But it tries to avoid territorial fights, being guided by the distinctive body smell of other tigers. Tigers fight to death only when a tigress is defending her young, or when a tiger is guarding a tigress from the attentions of other males. The popular image of the tiger is that of a merciless and unconquerable hunter. But studies show that it catches only one of 20 victims it tries to attack. Fears have recently developed that Project Tiger has been too successful. It has enabled the tiger population to double (by mid-80s) but India’s human population has also grown out of control. Currently it is 750 million and likely to be 900 million by the end of the century. Land problem is becoming serious and many rural people feel bitter about the fact that some rich forests are reserved for tigers. A growing number of attacks by tigers on man has added to the hostility.According to the passage, a tiger’s territory________.

A．remains unchanged
B．is often defended by tigresses
C．is the cause of most fights
D．expands as the tiger grows up

单项选择题

We use both words and gestures to express our feelings, but the problem is that these words and gestures can be understood in different ways. It is true that a smile means the same thing in any language. So does laughter or crying. There are also a number of striking similarities in the way different animals show the same feelings. Dogs, tigers and humans, for example, often show their teeth when they are angry. This is probably because they are born with those behavior patterns. Fear is another emotion that is shown in much the same way all over the world. In Chinese and in English literature, a phrase like "he went pale and begin to tremble" suggests that the man is either very afraid or he has just got a very big shock. However, "he opened his eyes wide" is used to suggest anger in Chinese whereas in English it means surprise. In Chinese "surprise" can be described in a phrase like "they stretched out their tongues!" Sticking out your tongue in English is an insulting gesture or expresses strong dislike. Even in the same culture, people differ in ability to understand and express feelings. Experiments in America have shown that women are usually better than men at recognizing fear, anger, love and happiness on people’s faces. Other studies show that older people usually find it easier to recognize or understand body language than younger people do.People’s facial expressions may be misunderstood because________.

A．people of different ages may have different understanding
B．people have different cultures
C．people of different sex may understand a gesture in a different way
D．people of different countries speak different languages

单项选择题

By 1970, according to a World Wildlife Fund report, only about 4,500 tigers survived throughout the world— half of them in India. Mr. Foresters, who followed and counted tiger footprints, estimated that in May 1972 only about 1,800 tiger existed in India. Project Tiger supported by W. W. F. was immediately launched. Nine tiger reserves were created, with armed guards protecting them. The project provided opportunities for researchers from India and abroad to study tigers in the reserves and gather previously unavailable information about their habits. Studies show that a male tiger may control a hunting territory of between 10 and 20 sq. kms. depending on its age, size and strength. The territory of a male includes the smaller territories of three or four tigresses. A tiger marks the boundaries of its territory by spraying urine (尿) and other bodily liquids on bushes. But it tries to avoid territorial fights, being guided by the distinctive body smell of other tigers. Tigers fight to death only when a tigress is defending her young, or when a tiger is guarding a tigress from the attentions of other males. The popular image of the tiger is that of a merciless and unconquerable hunter. But studies show that it catches only one of 20 victims it tries to attack. Fears have recently developed that Project Tiger has been too successful. It has enabled the tiger population to double (by mid-80s) but India’s human population has also grown out of control. Currently it is 750 million and likely to be 900 million by the end of the century. Land problem is becoming serious and many rural people feel bitter about the fact that some rich forests are reserved for tigers. A growing number of attacks by tigers on man has added to the hostility.Some people are afraid that Project Tiger________.

A．has failed to achieve its goal
B．has not received enough attention
C．has been carried too far
D．is not worth the money spent on it

单项选择题

By 1970, according to a World Wildlife Fund report, only about 4,500 tigers survived throughout the world— half of them in India. Mr. Foresters, who followed and counted tiger footprints, estimated that in May 1972 only about 1,800 tiger existed in India. Project Tiger supported by W. W. F. was immediately launched. Nine tiger reserves were created, with armed guards protecting them. The project provided opportunities for researchers from India and abroad to study tigers in the reserves and gather previously unavailable information about their habits. Studies show that a male tiger may control a hunting territory of between 10 and 20 sq. kms. depending on its age, size and strength. The territory of a male includes the smaller territories of three or four tigresses. A tiger marks the boundaries of its territory by spraying urine (尿) and other bodily liquids on bushes. But it tries to avoid territorial fights, being guided by the distinctive body smell of other tigers. Tigers fight to death only when a tigress is defending her young, or when a tiger is guarding a tigress from the attentions of other males. The popular image of the tiger is that of a merciless and unconquerable hunter. But studies show that it catches only one of 20 victims it tries to attack. Fears have recently developed that Project Tiger has been too successful. It has enabled the tiger population to double (by mid-80s) but India’s human population has also grown out of control. Currently it is 750 million and likely to be 900 million by the end of the century. Land problem is becoming serious and many rural people feel bitter about the fact that some rich forests are reserved for tigers. A growing number of attacks by tigers on man has added to the hostility.The author seems________.

A．to have a matter-of-fact attitude towards Project Tiger
B．to be enthusiastic about Project Tiger
C．to have a hostile attitude towards Project Tiger
D．to be satisfied with Project Tiger

单项选择题

We use both words and gestures to express our feelings, but the problem is that these words and gestures can be understood in different ways. It is true that a smile means the same thing in any language. So does laughter or crying. There are also a number of striking similarities in the way different animals show the same feelings. Dogs, tigers and humans, for example, often show their teeth when they are angry. This is probably because they are born with those behavior patterns. Fear is another emotion that is shown in much the same way all over the world. In Chinese and in English literature, a phrase like "he went pale and begin to tremble" suggests that the man is either very afraid or he has just got a very big shock. However, "he opened his eyes wide" is used to suggest anger in Chinese whereas in English it means surprise. In Chinese "surprise" can be described in a phrase like "they stretched out their tongues!" Sticking out your tongue in English is an insulting gesture or expresses strong dislike. Even in the same culture, people differ in ability to understand and express feelings. Experiments in America have shown that women are usually better than men at recognizing fear, anger, love and happiness on people’s faces. Other studies show that older people usually find it easier to recognize or understand body language than younger people do.In the same culture, ________.

A．people have different ability to understand and express feelings
B．people have the same understanding of something
C．people never fail to understand each other
D．people are equally intelligent

单项选择题

Nowadays, with women playing an ever-increasing role in all kinds of careers and professions, it is difficult to understand that there was a time when no medical school would accept a woman. They all said that only a man could be a doctor. An American, Elizabeth Blackwell, was determined to become the first woman doctor in the world. After a great deal of delay and opposition, she received, to her great surprise, a letter from the Dean of Geneva College informing her that she had been accepted. Much later, Elizabeth discovered what had actually happened when her application had been received by the College authorities. None of them wanted to have a woman student, but they did not wish to offend the influential Philadelphia doctor who had recommended her, so they hit on the expedient of turning the decision over to the students general meeting. They were quite certain that this would result in this alarming idea being turned down. But when the student body met, many of them thought it would be amusing to be the only medical college in the country which could boast that it was training some sort of Amazon as a woman doctor. Some genuinely believed that women should be treated equally. While others thought of the whole thing as a joke. So the vote in favor was carried unanimously, and the college authorities found, with dismay, that they would now have to admit Elizabeth. A few days after receiving the notification of her acceptance, Elizabeth was on the train for the two-day journey to Geneva College.It is unbelievable that in the past________.

A．no medical school
B．no good woman doctor
C．medical school would accept a woman student
D．woman medical student could become doctor

单项选择题

All that we really need to plot out the future of our universe are a few good measurements. This does not mean that we can sit down today and outline the future course of the universe with anything like certainty. There are still too many things we do not know about the way the universe is put together. But we do know exactly what information we need to fill in our knowledge, and we have a pretty good idea of how to go about getting it. Perhaps the best way to think of our present situation is to imagine a train coming into a switchyard. All of the switches(转辙器) are set before the train arrives, so that its path is completely determined. Some switches we can see, others we cannot. There is no ambiguity if we can see the setting of a switch; we can say with confidence that some possible futures will not materialize and others will. At the unseen switches, however, there is no such certainty. We know the train will take one of the tracks leading out, but we have no idea which one. The unseen switches are the true decision points in the future, and what happens when we arrive at them determines the entire subsequent course of events. When we think about the future of the universe, we can see our "track" many billions of years into the future, but after that there are decision points to be dealt with and possible fates to consider. The goal of science is to reduce the ambiguity at the decision points and find the true road that will be followed.According to the passage, it is difficult to be certain about the distant future of the universe because we________.

A．have too many conflicting theories
B．do not have enough funding to continue our research
C．are not sure how the universe is put together
D．have focused our investigations on the moon and planets

单项选择题

We use both words and gestures to express our feelings, but the problem is that these words and gestures can be understood in different ways. It is true that a smile means the same thing in any language. So does laughter or crying. There are also a number of striking similarities in the way different animals show the same feelings. Dogs, tigers and humans, for example, often show their teeth when they are angry. This is probably because they are born with those behavior patterns. Fear is another emotion that is shown in much the same way all over the world. In Chinese and in English literature, a phrase like "he went pale and begin to tremble" suggests that the man is either very afraid or he has just got a very big shock. However, "he opened his eyes wide" is used to suggest anger in Chinese whereas in English it means surprise. In Chinese "surprise" can be described in a phrase like "they stretched out their tongues!" Sticking out your tongue in English is an insulting gesture or expresses strong dislike. Even in the same culture, people differ in ability to understand and express feelings. Experiments in America have shown that women are usually better than men at recognizing fear, anger, love and happiness on people’s faces. Other studies show that older people usually find it easier to recognize or understand body language than younger people do.From this passage, we can conclude that________.

A．words are used as frequently as gestures
B．words are often found difficult to understand
C．words and gestures are both used in expressing feelings
D．gestures are more efficiently used than words

单项选择题

Nowadays, with women playing an ever-increasing role in all kinds of careers and professions, it is difficult to understand that there was a time when no medical school would accept a woman. They all said that only a man could be a doctor. An American, Elizabeth Blackwell, was determined to become the first woman doctor in the world. After a great deal of delay and opposition, she received, to her great surprise, a letter from the Dean of Geneva College informing her that she had been accepted. Much later, Elizabeth discovered what had actually happened when her application had been received by the College authorities. None of them wanted to have a woman student, but they did not wish to offend the influential Philadelphia doctor who had recommended her, so they hit on the expedient of turning the decision over to the students general meeting. They were quite certain that this would result in this alarming idea being turned down. But when the student body met, many of them thought it would be amusing to be the only medical college in the country which could boast that it was training some sort of Amazon as a woman doctor. Some genuinely believed that women should be treated equally. While others thought of the whole thing as a joke. So the vote in favor was carried unanimously, and the college authorities found, with dismay, that they would now have to admit Elizabeth. A few days after receiving the notification of her acceptance, Elizabeth was on the train for the two-day journey to Geneva College.Elizabeth Blackwell________.

A．already knew that her application would be approved
B．had never expected that she would be admitted
C．never doubted that she would become a medical student
D．always doubted the fact that she became a medical student

单项选择题

All that we really need to plot out the future of our universe are a few good measurements. This does not mean that we can sit down today and outline the future course of the universe with anything like certainty. There are still too many things we do not know about the way the universe is put together. But we do know exactly what information we need to fill in our knowledge, and we have a pretty good idea of how to go about getting it. Perhaps the best way to think of our present situation is to imagine a train coming into a switchyard. All of the switches(转辙器) are set before the train arrives, so that its path is completely determined. Some switches we can see, others we cannot. There is no ambiguity if we can see the setting of a switch; we can say with confidence that some possible futures will not materialize and others will. At the unseen switches, however, there is no such certainty. We know the train will take one of the tracks leading out, but we have no idea which one. The unseen switches are the true decision points in the future, and what happens when we arrive at them determines the entire subsequent course of events. When we think about the future of the universe, we can see our "track" many billions of years into the future, but after that there are decision points to be dealt with and possible fates to consider. The goal of science is to reduce the ambiguity at the decision points and find the true road that will be followed.What does the author see as the function of the universe’s unseen "switches"

A．They tell us which one of the tracks the universe will use.
B．They enable us to alter the course of the universe.
C．They give us information about the lunar surface.
D．They determine which course the universe will take in the future.

单项选择题

We use both words and gestures to express our feelings, but the problem is that these words and gestures can be understood in different ways. It is true that a smile means the same thing in any language. So does laughter or crying. There are also a number of striking similarities in the way different animals show the same feelings. Dogs, tigers and humans, for example, often show their teeth when they are angry. This is probably because they are born with those behavior patterns. Fear is another emotion that is shown in much the same way all over the world. In Chinese and in English literature, a phrase like "he went pale and begin to tremble" suggests that the man is either very afraid or he has just got a very big shock. However, "he opened his eyes wide" is used to suggest anger in Chinese whereas in English it means surprise. In Chinese "surprise" can be described in a phrase like "they stretched out their tongues!" Sticking out your tongue in English is an insulting gesture or expresses strong dislike. Even in the same culture, people differ in ability to understand and express feelings. Experiments in America have shown that women are usually better than men at recognizing fear, anger, love and happiness on people’s faces. Other studies show that older people usually find it easier to recognize or understand body language than younger people do.The best title for this passage may be________.

A．Words and Feelings
B．Words, Gestures and Feelings
C．Gestures and Feelings
D．Culture and Understanding

单项选择题

All that we really need to plot out the future of our universe are a few good measurements. This does not mean that we can sit down today and outline the future course of the universe with anything like certainty. There are still too many things we do not know about the way the universe is put together. But we do know exactly what information we need to fill in our knowledge, and we have a pretty good idea of how to go about getting it. Perhaps the best way to think of our present situation is to imagine a train coming into a switchyard. All of the switches(转辙器) are set before the train arrives, so that its path is completely determined. Some switches we can see, others we cannot. There is no ambiguity if we can see the setting of a switch; we can say with confidence that some possible futures will not materialize and others will. At the unseen switches, however, there is no such certainty. We know the train will take one of the tracks leading out, but we have no idea which one. The unseen switches are the true decision points in the future, and what happens when we arrive at them determines the entire subsequent course of events. When we think about the future of the universe, we can see our "track" many billions of years into the future, but after that there are decision points to be dealt with and possible fates to consider. The goal of science is to reduce the ambiguity at the decision points and find the true road that will be followed.In the last paragraph, the word "track" could best be replaced by which of the following

A．Band.
B．Rails.
C．Path.
D．Sequence.

单项选择题

Nowadays, with women playing an ever-increasing role in all kinds of careers and professions, it is difficult to understand that there was a time when no medical school would accept a woman. They all said that only a man could be a doctor. An American, Elizabeth Blackwell, was determined to become the first woman doctor in the world. After a great deal of delay and opposition, she received, to her great surprise, a letter from the Dean of Geneva College informing her that she had been accepted. Much later, Elizabeth discovered what had actually happened when her application had been received by the College authorities. None of them wanted to have a woman student, but they did not wish to offend the influential Philadelphia doctor who had recommended her, so they hit on the expedient of turning the decision over to the students general meeting. They were quite certain that this would result in this alarming idea being turned down. But when the student body met, many of them thought it would be amusing to be the only medical college in the country which could boast that it was training some sort of Amazon as a woman doctor. Some genuinely believed that women should be treated equally. While others thought of the whole thing as a joke. So the vote in favor was carried unanimously, and the college authorities found, with dismay, that they would now have to admit Elizabeth. A few days after receiving the notification of her acceptance, Elizabeth was on the train for the two-day journey to Geneva College.Why were students asked to decide on Elizabeth’s application

A．Because the college was democratic.
B．Because all the policy was decided by students in that college.
C．Because students were more fair than the authorities.
D．Because the college authorities believed that man students would not accept Blackwell meanwhile they would not offend the recommender.

单项选择题

Nowadays, with women playing an ever-increasing role in all kinds of careers and professions, it is difficult to understand that there was a time when no medical school would accept a woman. They all said that only a man could be a doctor. An American, Elizabeth Blackwell, was determined to become the first woman doctor in the world. After a great deal of delay and opposition, she received, to her great surprise, a letter from the Dean of Geneva College informing her that she had been accepted. Much later, Elizabeth discovered what had actually happened when her application had been received by the College authorities. None of them wanted to have a woman student, but they did not wish to offend the influential Philadelphia doctor who had recommended her, so they hit on the expedient of turning the decision over to the students general meeting. They were quite certain that this would result in this alarming idea being turned down. But when the student body met, many of them thought it would be amusing to be the only medical college in the country which could boast that it was training some sort of Amazon as a woman doctor. Some genuinely believed that women should be treated equally. While others thought of the whole thing as a joke. So the vote in favor was carried unanimously, and the college authorities found, with dismay, that they would now have to admit Elizabeth. A few days after receiving the notification of her acceptance, Elizabeth was on the train for the two-day journey to Geneva College.Unanimously (in the second paragraph ) means _______.

A．not the same
B．not agreed
C．not in the same way
D．all agree

单项选择题

All that we really need to plot out the future of our universe are a few good measurements. This does not mean that we can sit down today and outline the future course of the universe with anything like certainty. There are still too many things we do not know about the way the universe is put together. But we do know exactly what information we need to fill in our knowledge, and we have a pretty good idea of how to go about getting it. Perhaps the best way to think of our present situation is to imagine a train coming into a switchyard. All of the switches(转辙器) are set before the train arrives, so that its path is completely determined. Some switches we can see, others we cannot. There is no ambiguity if we can see the setting of a switch; we can say with confidence that some possible futures will not materialize and others will. At the unseen switches, however, there is no such certainty. We know the train will take one of the tracks leading out, but we have no idea which one. The unseen switches are the true decision points in the future, and what happens when we arrive at them determines the entire subsequent course of events. When we think about the future of the universe, we can see our "track" many billions of years into the future, but after that there are decision points to be dealt with and possible fates to consider. The goal of science is to reduce the ambiguity at the decision points and find the true road that will be followed.For whom is the author probably writing this passage

A．Train engineers.
B．Professors of statistics.
C．General audiences.
D．Young children.

单项选择题

Nowadays, with women playing an ever-increasing role in all kinds of careers and professions, it is difficult to understand that there was a time when no medical school would accept a woman. They all said that only a man could be a doctor. An American, Elizabeth Blackwell, was determined to become the first woman doctor in the world. After a great deal of delay and opposition, she received, to her great surprise, a letter from the Dean of Geneva College informing her that she had been accepted. Much later, Elizabeth discovered what had actually happened when her application had been received by the College authorities. None of them wanted to have a woman student, but they did not wish to offend the influential Philadelphia doctor who had recommended her, so they hit on the expedient of turning the decision over to the students general meeting. They were quite certain that this would result in this alarming idea being turned down. But when the student body met, many of them thought it would be amusing to be the only medical college in the country which could boast that it was training some sort of Amazon as a woman doctor. Some genuinely believed that women should be treated equally. While others thought of the whole thing as a joke. So the vote in favor was carried unanimously, and the college authorities found, with dismay, that they would now have to admit Elizabeth. A few days after receiving the notification of her acceptance, Elizabeth was on the train for the two-day journey to Geneva College.The students agreed to accept Elizabeth Blackwell as fellow student ______.

A．for some reason untold
B．they believed in equality of the sexes
C．so as not to offend the authorities
D．because they thought it would be amusing

单项选择题

All that we really need to plot out the future of our universe are a few good measurements. This does not mean that we can sit down today and outline the future course of the universe with anything like certainty. There are still too many things we do not know about the way the universe is put together. But we do know exactly what information we need to fill in our knowledge, and we have a pretty good idea of how to go about getting it. Perhaps the best way to think of our present situation is to imagine a train coming into a switchyard. All of the switches(转辙器) are set before the train arrives, so that its path is completely determined. Some switches we can see, others we cannot. There is no ambiguity if we can see the setting of a switch; we can say with confidence that some possible futures will not materialize and others will. At the unseen switches, however, there is no such certainty. We know the train will take one of the tracks leading out, but we have no idea which one. The unseen switches are the true decision points in the future, and what happens when we arrive at them determines the entire subsequent course of events. When we think about the future of the universe, we can see our "track" many billions of years into the future, but after that there are decision points to be dealt with and possible fates to consider. The goal of science is to reduce the ambiguity at the decision points and find the true road that will be followed.Which of the following statements best describes the organization of the passage

A．A statement illustrated by an analogy(类比).
B．A hypothesis supported by documentation (引出文献).
C．A comparison of two contrasting theories.
D．A critical analysis of a common assumption.

单项选择题

The accuracy of scientific observations and calculations is always at the mercy of the scientist’s time-keeping methods. For this reason, scientists are interested in devices that give promise of more precise time-keeping. In their search for precision, scientists have turned to atomic clocks that depend on various vibrating atoms or molecules to supply their "ticking". This is possible because each kind of atom or molecule has its own characteristic rate of vibration. Atom in ammonia, for example, vibrates or "ticks" 24 billion times a second. One such atomic clock is so accurate that it will probably lose no more than a second in 3000 years. It will be of great importance in fields such as astronomical observation and long-range navigation. The heart of this Atomichron is a cesium (铯) atom that vibrates 9. 2 billion times a second when heated to the temperature of boiling water. An atomic clock that operates with an ammonia molecule may be used to check the accuracy of predictions based on Einstein’s relativity theories, according to which a clock in motion and a clock at rest should keep time differently. Placed in an orbiting satellite moving at a speed of 18,000 miles an hour, the clock could broadcast its time readings on a similar model. Whatever differences develop would be checked against the differences predicted.The selection says that the accuracy of scientific observation depends on________.

A．methods of measurement
B．basic assumptions
C．time-keeping methods
D．earlier experiments

单项选择题

The accuracy of scientific observations and calculations is always at the mercy of the scientist’s time-keeping methods. For this reason, scientists are interested in devices that give promise of more precise time-keeping. In their search for precision, scientists have turned to atomic clocks that depend on various vibrating atoms or molecules to supply their "ticking". This is possible because each kind of atom or molecule has its own characteristic rate of vibration. Atom in ammonia, for example, vibrates or "ticks" 24 billion times a second. One such atomic clock is so accurate that it will probably lose no more than a second in 3000 years. It will be of great importance in fields such as astronomical observation and long-range navigation. The heart of this Atomichron is a cesium (铯) atom that vibrates 9. 2 billion times a second when heated to the temperature of boiling water. An atomic clock that operates with an ammonia molecule may be used to check the accuracy of predictions based on Einstein’s relativity theories, according to which a clock in motion and a clock at rest should keep time differently. Placed in an orbiting satellite moving at a speed of 18,000 miles an hour, the clock could broadcast its time readings on a similar model. Whatever differences develop would be checked against the differences predicted.Atomic clocks differ according to________.

A．function
B．the rate of vibration
C．the type of molecule or atom used
D．both B and C

单项选择题

The accuracy of scientific observations and calculations is always at the mercy of the scientist’s time-keeping methods. For this reason, scientists are interested in devices that give promise of more precise time-keeping. In their search for precision, scientists have turned to atomic clocks that depend on various vibrating atoms or molecules to supply their "ticking". This is possible because each kind of atom or molecule has its own characteristic rate of vibration. Atom in ammonia, for example, vibrates or "ticks" 24 billion times a second. One such atomic clock is so accurate that it will probably lose no more than a second in 3000 years. It will be of great importance in fields such as astronomical observation and long-range navigation. The heart of this Atomichron is a cesium (铯) atom that vibrates 9. 2 billion times a second when heated to the temperature of boiling water. An atomic clock that operates with an ammonia molecule may be used to check the accuracy of predictions based on Einstein’s relativity theories, according to which a clock in motion and a clock at rest should keep time differently. Placed in an orbiting satellite moving at a speed of 18,000 miles an hour, the clock could broadcast its time readings on a similar model. Whatever differences develop would be checked against the differences predicted.The Atomichron will be used in________.

A．making astronomical observations
B．measuring vibration rates
C．broadcasting
D．all of the above

单项选择题

The accuracy of scientific observations and calculations is always at the mercy of the scientist’s time-keeping methods. For this reason, scientists are interested in devices that give promise of more precise time-keeping. In their search for precision, scientists have turned to atomic clocks that depend on various vibrating atoms or molecules to supply their "ticking". This is possible because each kind of atom or molecule has its own characteristic rate of vibration. Atom in ammonia, for example, vibrates or "ticks" 24 billion times a second. One such atomic clock is so accurate that it will probably lose no more than a second in 3000 years. It will be of great importance in fields such as astronomical observation and long-range navigation. The heart of this Atomichron is a cesium (铯) atom that vibrates 9. 2 billion times a second when heated to the temperature of boiling water. An atomic clock that operates with an ammonia molecule may be used to check the accuracy of predictions based on Einstein’s relativity theories, according to which a clock in motion and a clock at rest should keep time differently. Placed in an orbiting satellite moving at a speed of 18,000 miles an hour, the clock could broadcast its time readings on a similar model. Whatever differences develop would be checked against the differences predicted.From the selection, we may assume that temperature changes________.

A．affect only ammonia molecules
B．may affect the vibration rate of atoms
C．affect the speed at which atoms travel
D．do not affect atoms in any way

单项选择题

The accuracy of scientific observations and calculations is always at the mercy of the scientist’s time-keeping methods. For this reason, scientists are interested in devices that give promise of more precise time-keeping. In their search for precision, scientists have turned to atomic clocks that depend on various vibrating atoms or molecules to supply their "ticking". This is possible because each kind of atom or molecule has its own characteristic rate of vibration. Atom in ammonia, for example, vibrates or "ticks" 24 billion times a second. One such atomic clock is so accurate that it will probably lose no more than a second in 3000 years. It will be of great importance in fields such as astronomical observation and long-range navigation. The heart of this Atomichron is a cesium (铯) atom that vibrates 9. 2 billion times a second when heated to the temperature of boiling water. An atomic clock that operates with an ammonia molecule may be used to check the accuracy of predictions based on Einstein’s relativity theories, according to which a clock in motion and a clock at rest should keep time differently. Placed in an orbiting satellite moving at a speed of 18,000 miles an hour, the clock could broadcast its time readings on a similar model. Whatever differences develop would be checked against the differences predicted.An appropriate title for this selection would be________.

A．A Peacetime Use of the Atom
B．The Satellite Timekeeper
C．Atoms and Molecules
D．The Role of the Clock

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