March 21 is World Sleep Day. How’s your sleep recently?
The Chinese Medical Doctor Association asked 8,200 people in China about their sleep. More than 36.3 percent of them said they often sleep badly. The study also finds that many students have only 5 hours of sleep a day. According to the US National Sleep Foundation, teenagers need 8.5 to 9 hours of sleep every night. What cuts into their sleeping time? Homework. Also, school starts early in the morning.
But bad sleeping habits also play a role. Do you like to have a look at your mobile phone before going to bed? The survey finds that 60 percent of people check their phones before they sleep. They read news, check their WeChat (微信) or chat with QQ friends.
It’s important for us to get enough sleep. We feel tired and think slowly. Besides, sleepy kids are often unhappy, says a study by the US National Sleep Foundation.
We can’t change our school time. But there are still ways to get better sleep. Stay away from coke, coffee and tea at night. They make it hard to fall asleep. Watch less television. Leave your mobile phone and tablet computer (平板电脑) on your desk.
根据短文内容，选择最佳答语，并在答题卡上按要求作答。
What cuts into students’ sleeping time?

A．Students like reading in bed before they sleep.

B．Students have got too much homework and school starts early in the morning..

C．Students often drink coke, coffee and tea at night.

D．Students check their WeChat or chat with QQ friends at night.

How do students behave in class when they don’t get enough sleep?

A．They don’t want to do their homework.

B．They sleep in class.

C．They feel excited.

D．They not only feel tired and unhappy but also think slowly.

How many hours should teenagers sleep every night according to the US National Sleep Foundation?

A．5 to 6 hours.	B．6 to 8 hours.
C．8.5 to 9 hours.	D．9 to 10 hours.

Which of the following is NOT true?

A．Drinking coke, coffee and tea at night is good for our sleep.

B．We can’t change everything but we can find many ways to get better sleep.

C．Bad sleeping habits aren’t good for us.

D．We should stay away from bad sleeping habits.

In this passage, the writer is mainly trying to make the readers realize__________.

A．March 21 is World Sleep Day

B．homework makes students have no enough time to sleep

C．we feel tired and think slowly because we have bad sleeping habits

D．good sleeping habits can help us stay healthy