题目内容：

Sleep and Weight

A couple of groups of researchers have found the reason why people are getting fatter. Researchers from the University of Chicago recruited (征募) 12 young men who came to their sleep lab on four different nights. Two nights, the men slept only four hours. The other two nights, they slept ten hours. Researchers Van Carter headed the study.

"After two nights of either short sleep or long sleep, we checked in their blood every 20 minutes or 30 minutes the levels of the hormone stimulating appetite (刺激食欲)."

They also checked the hormone that signals the brain when you're full. They found that when the men slept 10 hours, they woke up with normal levels of hormone and normal appetite. But when they slept only four hours, they had higher levels of hormone that stimulates appetite and lower levels of the hormone that signals fullness.

"Yeah, our study suggests that short sleep does modify the hormone that controls appetite in such a way that one is hungrier."

And not only were the men hungry, but also what they wanted to eat wasn't nutritious (有营养的).

"The foods that they preferred were candy, cookies, cake, ice cream, potato chips, pretzels, bread, pasta, rice, all high carbohydrate (碳水化合物) food."

Another study came to similar results. Researchers at Stanford University analyzed (分析) data from over 1, 000 volunteers who answered questions about sleep habits and also had their hormone levels measured. Psychiatrist (精神病专家) Emmmanuel Meno saw the same increase in the hormone stimulating appetite, and the same decrease (降低) in hormone that signals fullness.

"What's interesting about it is that it's counter-intuitive (反直觉的), because most people would say, 'Oh, yes. If you sleep a lot, you are lazy and you're going to be overweight.' and actually that's not what we observe (观察)."

Over the past forty years, American adults have cut down their average sleep time. They slept about eight and a half hours. Today, it's down to seven or less. Meno says Americans might want to reconsider (重新考虑) the amount of time they sleep.

"Now I think what we are finding is that it's important to sleep the right amount, and healthy sleep is as important as exercise and nutrition. I think, indeed, people who are overweight should sleep a little more. But if they treat better their sleep, it may help them to lose weight."

1.According to the passage, the researchers find that ________.

A.it's easier to get overweight if we don't have enough sleep

B.our emotions make great influence on the quality of sleep

C.we will lose weight more easily if we often stay up late

D.taking enough exercise will make us keep good shapes

2.According to the researches, short sleepers usually seem to ________.

A.have a pale face and feel very tired the next morning

B.feel a little hungry and have something to eat eagerly

C.have no sense of sleep and keep awake all the night

D.have high blood pressure and result as a bad headache

3.What does the underlined word "modify" mean in the passage?

A.provide B.prevent C.change D.improve

4.What can we infer from the passage?

A.Most of the Americans will insist on increasing their sleeping time.

B.Overweight people will control their food instead of taking exercise.

C.It's necessary to check the levels of hormone in our blood every day.

D.Americans are facing the problem of getting overweight at present.