In the days before electricity, people don’t worry much about sleep. They usually went to bed a couple of hours after sunset (日落) and woke at sunrise. After all, there wasn’t much to do in those days after the sun went down. But then came the electric light bulb (電燈泡). And now we have satellite television, the Internet,24-hour convenience stores, and longer hours at work. How much can we sleep? How much should we sleep?

Like it or not, many of us are sleeping less on average (平均). In 1910, most Americans slept 9 hours a night. That dropped to 7.5 hours by 1975. In 2002, a study by the National Sleep Foundation found that the average American got only 6.9 hours. The news is even worse for people who work the night shift. They sleep an average of just 5 hours.

Are we sleeping enough? Not if you believe in the old rule of eight hours of rest, eight hours of work, and eight hours of play. On the other hand, Norman Stanley, a British scientist who studies sleep, believes people’s sleep needs are different. Some people need as many as 11 hours, but others need as few as three. How much do you really need? “To find out,” he says, “simply sleep until you wake naturally, without the help of an alarm clock. That’s your sleep need.”

Meanwhile, other scientists and researchers are searching for new ways to keep us awake longer. Some are developing chemicals (化學(xué)藥品) that are safer and more powerful than caffeine, the chemical found in coffee and tea. One experimental drug, CX717, kept laboratory monkeys working happily for 36 hours. Further developments may allow people to safely stay awake for several days straight. One group of researchers is studying a gene (基因) found in some fruit flies that lets them get by on one-third the usual amount of sleep. Another group is even working on an electric switch that immediately wakes up a sleeping brain.

The meanings of this research are huge. On the one hand, this could lead to a world where we work longer and longer hours with less and less sleep. On the other hand, if we needed less sleep, we would have more free time to travel, read, volunteer, and spend time with family.

1.How many hours did most Americans sleep a night in 1975?

A. 5. B. 6.9. C. 7.5. D. 9.

2.What can we learn from the passage?

A. People have got enough sleep. B. People will work longer hours.

C. Sleep time will be a big problem. D. Staying awake for long is possible.

3.What is probably the best title of the passage?

A. To sleep or Not to sleep? B. How can We Sleep Longer?

C. To Work or Not to Work? D. How Much We can Sleep?

1.C 2.D 3.A 【解析】我們到底每晚需要多少睡眠呢?過(guò)去我們總是認(rèn)為至少要八個(gè)小時(shí)的睡眠,但文章中作者告訴我們,不同的人需要的睡眠時(shí)間也是不一樣的。而且現(xiàn)在科學(xué)家們和研究人員還在尋找一些新的方法可以讓人們清醒的時(shí)間更長(zhǎng)。 1.細(xì)節(jié)理解題。根據(jù)短文第二段中Like it or not, many of us are sleeping less on average (...
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