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单项选择题
Genes that control factors such as size, color and shape determine the differences in fruit. And now that scientists have discovered how to detect different genes, farmers can hand over a young and tender branch to have its genes checked prior to planting. It works the same way as a detective (侦探) checking finger-prints. Once farmers know which trees are good and which are bad, they can discard the bad ones. Farmers can even create new varieties according to their individual tastes.
In the past three years, tens of thousands of tests were carried out to determine the genetic (基因的) features of fruit. Zhang, a Chinese scientists, showed a photo of a DNA (脱氧核糖核酸)-test and pointed to the shining lines on it, saying that the lines were genetic signs that tell us what a tree’s fruit will be like. For example, the ordinary pear tree bears fruit after four years. But now it only takes a month to test the DNA from a young leaf and a farmer will know everything about its fruit. By mixing different types of trees with suitable genes, farmers can create whatever fruit trees they want.
A. the examination of human finger-prints
B. the development of new varieties of fruit
C. the checking of young and tender branches
D. the distinction between bad trees and good ones
填空题
填空题
单项选择题
A. admitted
B. permitted
C. allowed
D. accepted
单项选择题
A. What
B. That
C. Because
D. Since
