题目

阅读理解     Hacking isn't just for computers and smartphones, According to a study published last week in the journal Science, scientists have found a way to hack a plant's genes in order to make it use sunlight more quickly. Someday, the results could increase the amount of food produced around the world.     Photosynthesis（光合作用）is the word used to describe how plants use sunlight, water, and carbon dioxide to make their own food. Scientists who conducted the new study say this is a very slow process. Plants use less than 1 percent of the energy available to therm. But by hacking a plant's genes, the scientists were able to increase the amount of leaf growth on plants between 14 and 20 percent.     "Specifically, scientists hacked the plant's protective system. Normally, this system is activated when a plant gets too much sunlight, "said scientist Krishna Niyogi, co-author of the study. When the plant senses the light, it gets rid of extra energy and creates more leaves. When the plant is in shade, the protective system is turned off, but the process is slow.     Stephen Long is the lead author of the study. He compared a plant's protective system to light-adjusting glasses. When a person wears the glasses outside during the day, the lenses（镜片）darken and lighten depending on how sunny it is. Plants do the same thing, he said. But in plants the adjustment can take anywhere from 10 minutes to an hour. This makes it hard for plants to get the right amount of sunlight needed to create food.     The new study sped up the process. By changing the plant's genes, the protective system turned on and off more quickly than normal. As a result, leaf growth on the plants scientists used in the study increased. Leaf growth in two plants increased by 20 percent, while leaf growth on a third plant increased by 14 percent. Scientists conducted the study on tobacco plants. But they think the genetic changes will produce the same results in corn and rice. （1） What will happen to the plants when scientists change plants' genes？ A . They will become weaker and weaker. B . They will grow fast to produce more food. C . They will have more beautiful flowers. D . They will depend less on sunlight. （2） Why does the author mention light-adjusting glasses？ A . To warn people of the hot and bright sun. B . To explain the principle of plants' protective system. C . To help leaves of the plants absorb sunlight. D . To serve the science experiment smoothly. （3） In the future, the genetic changes will be used to. A . improve tobacco plants' quality B . increase tobacco plants' leaves and roots C . improve the flowers' living time D . increase the production of corn and rice （4） Which of the following can be the theme of this text？ A . Hacking plants for more production B . Leaf growing more quickly C . Double production of tobacco plants D . Photosynthesis and production 答案： B B D A

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