Researchers have found that REM (rapid eye movement) sleep is important to human beings. This type of sleep generally occurs four or five times during one night of sleep lasting five minutes to forty minutes for each occurrence. The deeper a person’s sleep becomes, the longer the periods of rapid eye movement.

There are physical changes in the body to show that a person has changed from NREM (non-rapid eye movement) to REM sleep. Breathing becomes faster, the heart rate increases, and, as the name implies, the eyes begin to move quickly.

Accompanying these physical changes in the body is a very important characteristic of REM sleep. It is during REM sleep that a person dreams.

1. According to the passage, how often does REM sleep occur in one night?

A. Once

B. Twice

C. Four of five times

D. Forty times

2. The word “deeper” in paragraph 1 is closest in meaning to which of the following?

A. heavier

B. louder

C. stronger

D. happier

3. Which of the following shows that a person is NOT dreaming in his sleep?

A. His eyes begin to move.

B. His breathing becomes faster.

C. His heart rate increases.

D. His eyes stop moving.

4. The subject of this passage is ________.

A. why people sleep

B. the human need for REM sleep

C. the characteristic of REM sleep

D. physical changes in the human body

5. Which of the following is the best title of the article?

A. REM Sleep

B. Two Types of Sleep

C. Sleepers

D. What Happens to Sleepers

【标准答案和解析】

1. C. 细节题。定位到文章第一段第二句可以知道是原词再现，所以答案选C。

2. A. 词义题。从文章中可以知道，人睡得越熟，快速眼部运动的时间就持续得越久。那么可以知道这里的deeper是表示程度很深，所以答案选A。

3. D. 细节题。定位到第二段第二句可以知道A,B,C都是文章中提到的，只有D眼睛会停止运动肯定是不对的。所以答案选D。

4. C. 主旨题。A选项说人们为什么睡觉，文章没有讲原因，不正确。B选项说人类需要REM睡眠，也不正确。C选项说REM睡眠的特征，正是文章全篇所探讨的，正确。D选项说人类身体发生的物理变化，跟文章主旨无关，不正确。所以答案选C。

5. A. 主旨题。根据文章开头第一句主旨句可以知道，文章主要就是在阐述REM睡眠，而A选项就是REM睡眠情况，所以答案选A。