综合类C级：阅读理解sleep necessary
burning the midnight oil before an exam or interview does harm to the performance according to a recent research which found that sleep is necessary for memories to be taken back into the brain. a good nights sleep within 30 hours of trying to remember a new task is a required condition of having good recall in the weeks ahead， scientists have found.
the research， published in the december issue of nature neuroscience， showed that it was the act of sleep， rather than the simple passage of time， that was critical for long-term memory formation.
"we think that getting that first nights sleep starts the process of memory consolidation (巩固)，" said robert stickgold， a sleep researcher at harvard medical school who conducted the latest study.
"it seems that memories normally wash out of the brain unless some process nails them down. my suspicion is that sleep is one of those things that does the flailing down，" professor stickgold said.
with about one in five people claiming that they are so chronically short of sleep that it affects their daily activities， the latest work emphasizes the less well-understood side effect- serious memory impairment (损害).
volunteers in an experiment found it easier to remember a memory task if they were allowed to sleep that night. but for those kept awake， no amount of subsequent sleep made up for the initial loss.
professor stickgolds team trained 24 people to identify the direction of three diagonal (斜线形的) bars flashed for a sixtieth of a second on a computer screen full of horizontal (水平的) stripes.
half of the subjects were kept awake that night， while the others slept. both groups were allowed to sleep for the second and third nights to make up for any differences in tiredness between the volunteers.
those who slept the first night were significantly and consistently better at remembering the task while the second group showed no improvement despite enjoying two nights of catch-up sleep.
1 the research published in nature neuroscience showed that what was essential to the formation of long-term memory was
a intelligence.
b time.
c food.
d sleep.
2 which of the following statements about the research is not true?
a it was done within 30 hours.
b it was headed by professor stickgold.
c it focused on long-term memory formation.
d there were altogether 24 subjects in the experiment.
3 stickgolds research focused on the side effect produced by
a memory impairment.
b lack of sleep.
c low work efficiency.
d memory recall.
4 in stickgolds experiment， those who were kept awake on the first night
a could very well remember the direction of the diagonal bars.
b didnt do any better after two nights sleep.
c were as tired as those who were not.
d could recall the direction of more bars than those who were not.
5 those who slept the first night
a couldnt remember the task.
b could not sleep the second and third nights.
c performed slightly better than those who did not
d did much better than those who did not.