It can remind you a warm sunny day．A.onB.inC.ofD.to 题目和参考答案——青夏教育精英家教网—

Dreams can happen in any of the four stages of sleep. The most memorable and clearest dreams happen in the last stage of sleep (also known as REM sleep). The sleep cycle repeats about four to five times every night. So you can see how a person has several different dreams in one night. Most people only remember dreams that happen closer to the morning when they are about to wake up. That you can’t remember those dreams does not mean they never happened.
The stages in the sleep cycle are organized by the changes in different brain activities.

Stage 1: You are entering into light sleep. In this stage, your eyes move rapidly. We call this NREM. The body gets relaxed and your body temperature lowers. Your heart rate lowers, too. The body is preparing to enter into deep sleep.
Stage 2: Also characterized by NREM. In this stage, the body temperature and heart rate drop again. You are completely asleep.
Stage 3: Still in the NREM stage, this is a deeper sleep still.
Stage 4: In this stage of sleep, your eyes move back or forward. We call it REM sleep. This stage happens at about 90-100 minutes after the beginning of sleep. Your blood pressure rises, heart rate speeds up. The majority of your dreams happen in this stage.
These stages repeat themselves throughout a night’s sleep.
【小题1】 Dreams can happen in ___________.
A. Stage 1 and 2           B. Stage 3 and 4            C. every stage
【小题2】Which of the following sentences is TRUE according to the passage?
A. These stages will happen once or twice one night.
B. Most people only remember the dreams that happen when they are about to wake up.
C. If one can’t remember his dreams, he never dreams at all.
【小题3】What will happen in Stage 2?
A. Eyes move rapidly.   B. People enter into light sleep.    C. Heart rate drops.
【小题4】The first REM sleep happens about ___________ after the starting of sleep.
A. 1 to 2 hours                     B. 2 to 3 hours                     C. 10 minutes
【小题5】The passage is mainly about ___________.
A. the stages of sleep     B. types of dreams         C. remembering dreams

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 ________.

A．stop

B．increase

C．decrease

D．stay the same

【小题2】Which word in paragraph（段落）3 means “colorful and lively”?

【小题3】Which paragraph tells what happens when people don’t get enough sleep?

【小题4】What is the main idea of the article?

A．REM sleep helps the brain grow.

B．REM sleep has been watched and recorded by scientists.

C．REM sleep is a time to empty the day’s garbage.

D．REM sleep is an active time when the body is hard at work.

【小题5】You can decide from the article that REM sleep ________.

A．has a restful effect on people

B．can be avoided with lots of sleep

C．is something that all people experience

D．is something that all scientists agree on

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 ________.