Question

Some people can stay up all night and still get work done the next day.I'm not one of them.After a night without enough sleep, I feel badtempered.I have trouble remembering things.And all I want to do is to crawl into bed and sleep.

How do you feel after you've stayed up late to finish schoolwork? Or the day after an overnight party? Scientists now say that your answers to these questions may depend on your genes.

New research suggests that a gene called “period 3” affects how well you function without sleep.The “period 3” gene comes in two forms：short and long.Everyone has two copies of the gene.So, you may have two longs, two shorts, or one of each.Your particular combination depends on what your parents passed on to you.

Scientists from the University of Surrey in England studied 24 people who had either two short or two long copies of “period 3”．Study participants had to stay awake 40 hours straight.Then，they took tests that measured  how quickly they pushed a button when numbers flashed on screen and how well they could remember lists of numbers.

Results showed that the people with the short form of “period 3” performed much better on these tests than the people with the long form did.In both groups，people performed worst in the early morning.

After the first round of experiments，participants were finally allowed to sleep.People in the group that performed well on the tests (those with the short form of “period 3”) took about 18 minutes to nod off.

People with the long “period 3” gene, by contrast, fell asleep in just 8 minutes.They also spent more time on deep sleep.That suggests that people with the long form of the gene need more and deeper sleep to keep their brains working in top form.

I think I must have the long form of“period 3”．What about you?

1.The purpose of this passage might be________.

A．to tell us the importance of plenty of sleep

B．to tell the result of a research on sleepy gene

C．to inform the harm of lacking sleep

D．to announce the sleeping rules of humans

2.Which of the following decides how well you perform without sleep?

A．One short form.

B．One long copy.

C．One short and two long copies.

D．Period 3.

3.What kind of people need less sleep according to the research?

A．Those with two long copies of the gene.

B．Those with two short copies of the gene.

C．Those with one short and one long copy of the gene.

D．Those with three short copies of the gene.

4.If one lacks enough sleep，one should avoid doing important or dangerous things

________.

A．at dawn  B．at night

C．in the afternoon  D．at noon

Answer

1.B

2.D

3.B

4.A

【解析】

1.答案 B [主旨大意题。文章的目的就是介绍一项关于睡眠的实验结果(文章第三段为主题段)。]

2.2】答案 D [细节理解题。人们缺乏睡眠时表现的好坏由“period 3”决定。根据第三段第一句话可知答案。]

3.3】答案 B [细节理解题。由文章第五段可得出答案。]

4.4】答案 A [推理判断题。根据第五段第二句“In both groups，people performed worst in the early morning.”得出答案。缺乏睡眠的人在黎明时表现最差，因此不能在此时做重要或危险的事情。]