March 16 is International Sleep Day． Studies have shown that a good night's rest helps us stay healthy， both mentally（精神地） and physically（身体地）． Sleep is probably the best tool we have for memory and learning． A good night's sleep helps to learn better．

   But what about getting rest during the middle of the day？ Short periods of sleep after a mid﹣day meal， we call it napping（午睡）， may help our brains work better．

   Past studies have shown that napping can help babies and young children learn better． And napping can help brain performance in older adults． Taking a nap may also help this group of peoplefight off age﹣related memory loss． As we all know， the older we are， the more memory we will lose．

   The study found that people who took an hour﹣long nap did much better on mental tests than those who did not nap． The hour﹣long nappers also did better on the tests than those who napped for shorter and longer periods． In this study， it seems that the most effective（有效地） nap lasted for about an hour， but not much longer． Keep in mind， however， that these are the findings for those over the age of 65．

And there is a little difference between the old and young people． Doctor Michael Twery notes that an hour long nap may be too long for young， healthy adults． And 30 minutes is enough to remove the pressure to sleep and will help them feel more awake（清醒的）． If they nap longer， they will get trapped into（受困于） deep sleep， which can be hard to get out of．

If you have trouble falling asleep at night， limit（限制） your daytime nap to under 45 minutes． Also nap before 3 p．m． in the afternoon．

（1）When is the International Sleep Day？ 　　

A．	January16．
B．	February16．
C．	March 16．
D．	May 16．

（2）This group of people refers to（指的是） 　　．

A．	babies
B．	young children
C．	older adults
D．	young， healthy adults

（3）People who are over the age of 65 should spend 　　napping．

A．	10 minutes
B．	30 minutes
C．	under 45 minutes
D．	about an hour

（4） 　　30 minutes is enough for the young， healthy adults to remove the pressure and help them feel more awake．

A．	Napping
B．	Walking
C．	Swimming
D．	Dancing

（5）If you 　　， you should reduce your nap time and nap before 3 p．m． in the afternoon．

A．	are having trouble seeing
B．	have trouble making decisions
C．	have trouble remembering things
D．	have trouble falling asleep at night