Do you know why you sleep? You may think it’s because you’re tired. Or perhaps you’ve been told sleep is good for you. Yet no one knows exactly why or how people sleep.
Until the early 1950s, most scientists thought the body and brain rested during sleep. Then a scientist watched people sleep. He noticed that during periods of between 5 and 30 minutes each, sleepers’ eyes made rapid movements, as if they were watching something. He called these periods REM sleep, for Rapid Eye Movement. Periods when sleepers’ eyes did not move he called non-REM sleep.
Whenever the scientist woke people during REM sleep, they were having vivid dreams. Measurements showed that sleepers’ pulses（脉搏）went up quickly during REM sleep. Their breathing, heartbeat, and the blood going to the brain also increased. Far from being a time of rest, REM sleep is a time when the body is hard at work. Scientists still don’t know the reason for this. Some believe REM sleep makes learning easier. Babies spend a lot of time in REM sleep. Because of this, some scientists believe that REM sleep helps the brain grow. Others think REM sleep is a time for the brain to empty the day’s garbage.
One thing all the scientists agree on is that sleep is necessary. Without enough sleep, people make mistakes. Most major car accidents happen during the early morning hours, when people are sleepiest.
【小题1】During REM sleep, a person’s breathing and heartbeat ________.

You probably know you should say” please” and “thank you ” at restaurants. You probably know the rules of a library. You know you should respect and be nice to your classmates. But do you have music manners?

Keep It Down! You have to notice the volume of your music. You should not play your music so loud that everyone around you can hear it. Some people might even get angry. Usually, when you play the music loud on an MP3 player, other people can’t hear the words of the song. They just hear a loud sound. Not one wants to listen to this. Very loud music can also be bad for your ears, so even if you are alone when listening to our MP3 player, you shouldn’t have it turned up too high.

Take Them off! You need to know when to turn your MP3 player off and put it away. Libraries and schools don’t allow MP3 players. There are other places, like museums, that don’t have rules, but it would be rude to have your MP3 player on. Sometimes, it just doesn’t make sense to listen to your MP3 player at event. Why would you listen to music at a play, a movie or a sporting event? You would miss what is going on and others would wonder why you even came.

Take One Out! Once in a while it’s okay just to take out one earphone and not other. Imagine you are listening to your MP3 player when someone asks you the way. It would not be rude to take out one earphone, tell him the way, and put back the earphone and continue listening. You can also do this when you order food at a fast-food restaurant or when you answer the telephone and it’s not for you.

It’s Your Choice! There are times when you need to decide what is best. For example, some people can listen to music on their MP3 Players when read books, while others think it is disturbing. In cases like this, you need to do what seems right for you.

1.The underlined word “volume” in Paragraph Two probably means” _____.

A．the type of music                       B．the amount of a sound

C．the length of a song                      D．the colour of and MP3 player

2.No one wants to listen to _____ from others’ MP3 player.

A．a loud sound                           B．sad stories

C．a long movie                           D．the words of a song

3.We can take one earphone out when we _____.

A．show others the way                     B．talk to fiends on the phone

C．watch a sporting event                   D．have dinner with our parents

4.It’s all right to use our MPS player in _____.

A．schools           B．libraries           C．restaurants        D．museums

5.What can be the best title of this passage?

A．Music Lovers       B．Music Manners     C．MP3 Players       D．MP3 Earphones