leep is very important to human beings. The average person spends 220,000 hours, about a third of his life time, sleeping. Until about 30 years ago, no one knew much about sleep, although doctors and scientists have done research in sleep laboratories, they have learn a great deal by studying people as they are sleeping, but there is still much that they don’t understand. Sleeping, which is known as a biological need, is the resting state in which the body is not active and the mind is unconscious but your brain never really sleeps. It is never actually blank. The things that were on your mind during the day are still there at night. They appear as dreams which people have discussed for years. Sometimes people believed that dreams had magical powers or that they could tell the future! You may have sweet dreams or sometimes night-mares, which is terrifying. Sleep is very important to humans. We spend a third of our life sleeping, so we need to understand everything we can about sleep.

1.How long does an average person sleep during his life time?

A. 30 years       

B. one third year           

C. one third           

D. one second of his life

2. Doctors and scientists ……………

A. don’t know anything about sleep

B. have learnt much about sleep

C. think there is still things that they don’t understand

D. b and c are both correct

3. Sleeping is …………….. need .

A. natural     

B. physical                     

C. psychological   

D. biological

4. When we sleep ………………

A. our brain sleep too                                    

B. our brain still works 

C. our brain stops working                      

D. our brain is quite blank

5. “nightmare” is……………………

A. frightening dream                        

B. important dream 

C. magical dream                                    

D. sweet dream