During sleep, the fatigue (疲劳) of the body disappears and recuperation ( 恢复) begins. The tired mind gathers new energy. Once awake, the memory improves, and annoyance and problems are seen in a better perspective.Some adults require little sleep; others n

During sleep, the fatigue (疲劳) of the body disappears and recuperation ( 恢复) begins. The tired mind gathers new energy. Once awake, the memory improves, and annoyance and problems are seen in a better perspective.

Some adults require little sleep; others need eight to ten hours in every twenty-four. Infants sleep sixteen to eighteen hours daily and, as they grow older, the amount gradually diminishes. Young students may need twelve hours; university students may need ten. A worker with a physically demanding job may also need ten, whereas an executive worker under great pressure may manage on six to eight. Many famous people are reputed to have required little sleep. Napoleon, Thomas Edison and Charles Darwin apparently averaged only four to six hours a night.

Whatever your individual need, you can be sure that by the age of thirty you will have slept for a total of more than twelve years. By that age you will also have developed a sleep routine: a favorite hour, a favorite bed, a favorite position, and a formula you need to follow in order to rest comfortably. Investigators have tried to find out how long a person can go without sleep. Several people have reached more than 115 hours ?nearly five days, whereas animals kept awake for from five to eight days have died of exhaustion. The limit for human beings is probably about a week.

1、The writer implies that _________

A、sleep is important for good mental and physical health

B、a light sleep is as restful as a deep sleep

C、memory is improved during sleep

D、sleep is relatively unimportant for human beings

2、From the amount of sleep Napoleon, Edison and Darwin required, we can infer that_______.

A、they were famous great men

B、 they were executive workers

C、 they were intelligent people

D、 they were involved in mentally demanding work

3、The amount of sleep required ________.

A、varies greatly from individual to individual

B、 depends on an individual''s age

C、 relates to an individual''s occupation

D、 all of the above.

4、According to the passage, the sleeping routine will be built at the age of _________.

A、10

B、20

C、30

D、40

5、From animal experiments, we can conclude that the final result of the lack of sleep is probably _________

A、mental illness

B、mental breakdown

C、susceptibility to illness

D、death