food, wash, before, your, eating, hands
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need, classroom, I, right now, clean, the
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be strict in, you, should, study, your
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do, red, you, know, who, the girl, in, is
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Hawking is considered to be the 1.(great) scientist in history since Albert Einstein. He came up with 2. theory that the universe(宇宙) began with the Big Bang(大爆炸)and will end in black holes. He also wrote 3.(book) to help common people understand the universe. His most famous book is A Brief History of Time, which has 4.(sell) more than 10 million copies around the world.
Besides his 5.(science) achievements, Hawking was also someone who had a strong will(意志) 6. optimistic(乐观的)attitude.
When Hawking was 21, he got a serious illness that stopped 7.(he) from walking and talking. Later in life, he had to sit i8. a wheelchair and “speak” using a computerized voice. But this didn't stop him from living a meaningful and colorful l9.. “If one is 10.(physical) disabled, one cannot afford to be psychologically(心理上) disabled as well，” he once said.
In today's world, sleep experts often say that for a better night's rest, Americans should turn off their smart phones or iPads before sleeping. Such electronic products make the brain more active, and then influence their sleep. But according to a latest survey, more than 90% of Americans often use a computer or some other kinds of electronic products in the hour before bed.
Researchers find that manmade light from some electronic products at night may reduce the brain chemicals that help to sleep. In the study, the researchers let volunteers read, play games and watch movies on a screen for different time while measuring how much light their eyes received. They found that two hours of sitting before a bright screen at night reduced the sleep chemical levels by about 22%.
Then the researchers studied the college students who often used computers at night. They got the similar results. And researchers say that may not only cause sleeplessness, but also raise the risk of obesity(肥胖症), diabetes(糖尿病) and other diseases.
To be on the safe side, the researchers suggest that we should use computer less than before, or turn down our screens as much as possible before sleeping.
说明：21、22题完成句子；23题简略回答问题；24题用英语简要概括文章的主旨大意；25题将文中画线句子译成汉语。
1.Electronic products can ______________ and influence people's sleep.
2.Manmade light______________ may reduce the brain chemicals which help to sleep at night.
3.What did researchers let volunteers do in the study?
___________________________________
4.The passage mainly tells us _____________________________________.
5.________________________________________________________________________
