填空题

Questions 47 to 56 are based on the following passage.
During sleep, the fatigue 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 (47) .
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 (48) job may also need ten, whereas an (49) worker under great pressure may manage on six to eight. Many famous people are reputed to have (50) little sleep.
Whatever your (51) 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 (52) : a favorite hour, a favorite bed, a favorite position, and a (53) you need to follow in order to rest (54) .
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 five to eight days have died of (55) . The (56) for human beings is probably about a week.

• A) convenientlyI) formula
• B) requiredJ) acquired
• C) perspective K) comfortably
• D) corresponding L) exhaustion
• E) routine M) starvation
• F) limit N) prospective
• G) demanding O) executive
• H) individual