题目内容：

    The results from the world’s largest sleep study have shown that people who sleep on average between 7 to 8 hours per night perform better cognitively (认知地) than those who sleep less or more than this amount.

The world’s largest sleep study was launched in June 2018 and within days more than 40,000 people from the world participated in the online scientific investigation, which included an in-depth questionnaire and a series of cognitive performance activities.

“We really wanted to capture the sleeping habits of people around the entire globe. Obviously, there have been many smaller sleep studies of people in laboratories but we wanted to find out what sleep is like in the real world,” says Adrian Owen, western’s researcher in Cognitive Neuroscience and Imaging. “People who logged in gave us a lot of information about themselves. We had a fairly extensive questionnaire and they told us things like which medications they were on, where they were in the world and what kind of education they’d received because these are all factors that might have contributed to some of the results.”

More than half of all participants reported typically sleeping less than 6.3 hours per night, about an hour less than the study’s recommended amount. One shocking truth was that most participants who slept four hours or less performed as if they were almost nine years older.

Another surprising discovery was that sleep affected all adults equally. The amount of sleep associated with highly functional cognitive behavior was the same for everyone, regardless of age. Also, the harm associated with too little, or too much sleep did not depend on the age of the participants.

“We found that the best amount of sleep to keep your brain performing its best is 7 to 8 hours every night. We also found that people that slept more than that amount were equally harmed as those who slept too little,” says Conor Wild, Owen Lab Research Associate and the study’s lead author.

1.Where did the study take place?

A. In a lab. B. In the street.

C. On TV. D. On the Internet.

2.What may affect the result of the study according to Owen?

A. Career. B. Diet.

C. Education. D. Exercise.

3.What’s Wild’s view?

A. Sleeping too much is as bad as sleeping too little.

B. People must sleep for eight hours every night.

C. Sleeping too little can make people look older.

D. People needn’t pay attention to the amount of sleep.

4.What can we learn from the text?

A. Owen and Wild are the first to study sleep.

B. Lack of enough sleep is a common problem.

C. All the people in the world show interest in the study.

D. There is no effective way to solve the sleep problem.