5. It's very (hand) having a light above your desk.
鴻圖圖書寒假作業假期作業吉林大學出版社系列答案科目：高中英語 來源： 題型：
4. 有一天，克魯索沿著沙灘走向他的船時，在沙子里看見一個人的腳印。
One day, ， Crusoe saw in the sand the mark of a man's footprints.
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科目：高中英語 來源： 題型：
3. After three hours of bitter fighting,an entire enemy column (隊伍)
(摧毀) .
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Researchers at the University of California,San Francisco have discov?ered a gene that might explain why some people need less sleep than others. Experts say the finding opens the door into the study of sleep.
Even so,Ying-Hui Fu of the University of California? San Francisco says little is known about this basic human need. "We know very little about sleep. We don't know how our sleep is regulated," she said. "We don't know why some people need more sleep;why some people need less sleep;why most of us need eight hours of sleep;why,when we don't sleep,we don't function very well. We just don't know much about sleep at all.” Fu says sleep can be stimulated in humans when they drink alcoholic bev?erages or take sleeping pills. But she says no specific gene had been discovered that appeared to be involved in regulating sleep—until now.
Fu's research team found the sleep gene by accident while looking for a molecular mechanism (分子機制) .In the course of their studies,Fu says re?searchers identified a genetic mutation in people who go to bed at a normal time but sleep for only about six hours,feeling as refreshed when they wake up as those who appear to need eight hours or more of sleep.
Investigators genetically engineered mice to carry the mutation,and com?pared their sleep cycles and brain activity to others that did not have. They found that those with the gene slept less and were awake for longer periods of time. Mice with the mutation were also more energetic than normal mice,af?ter being deprived of sleep for 24 hours.
Although the gene mutation is thought to be extremely rare,Fu says it is a significant find for sleep researchers. "We essentially don't know anything about how sleep is regulated," she says. "But this gene is kind of opening a door for us to say, ' Now we have this gene and we know it affects human sleep quantity.，” Fu adds that the gene might be related to other medical conditions.
1. What have the researchers discovered?
A. How our sleep is regulated.
B. Why some people need less sleep than others.
C. Why most of us need eight hours of sleep.
D. Why we don't function very well.
2. According to the passage,we can know .
A. the gene can make the body awake longer
B. the gene extends people's sleep
C. the gene can improve people's sleep quality
D. the gene mutation can be found in each one
3. Which is the best title for this passage?
A. People need right sleep
B. Gene and sleep
C. Researchers discover the secret of sleep
D. Researchers discover the gene that affects sleep
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