People spend almost a third of their lives doing one thing﹣sleeping， Every year， there is a special day for people around the world to celebrate the importance of good and healthy sleep﹣World Sleep Day．

Sleep is like food for the brain．（1） 　　．

People of different ages need different amounts（数量）of sleep．According to the National Sleep Foundation（国家睡眠基金会）in the US，adults should get seven to eight hours of sleep a night．（2） 　　And school﹣aged children may need more than ten hours of sleep．

（3） 　　The China Youth and Children Research Center said that about 80 percent of middle school students don't get enough sleep． It has influenced on students' school life．（4） 　　They can't pay attention in class or do well in sports．

To solve this problem， scientists advise that students should get less schoolwork and more time to sleep．（5） 　　Good sleep habits help a lot． For example， try to go to sleep and wake up at the same time every day， even on weekends and during holidays．

A． Teenagers need nine to ten hours． B． If you sleep less， you' ll get fatter and fatter． C． Enough sleep helps the brain and body grow． D． Taking a 20﹣minute sleep at noon is also useful． E． Students without enough sleep may get poor grades． F． However，many students don't get enough sleep because of too much homework．