题目内容
The traditional view is we sleep because our brain is “programmed”to make us do so.
A．when
B．why
C．whether
D．that
D
解析： that引导表语从句，用来说明主语的内容。根据句意，空格内要填that，说明主语The traditional view的内容。
Being alone in outer space can be frightening. That is one reason why astronauts on solo（单独的） space flight were given plenty of work to keep them 45 . They were also in constant communication with people on the earth, 46 , being with people from whom you cannot get away might be even harder than being alone. This is what happens on long submarine（潜水艇） voyages. It will also happen on 47 space flights in the future. Will there be special problems of adjustment under such conditions?
Scientists have studied the reactions of men to one another during long submarine voyages. They have found that the longer the voyage lasts, the more serious the problem of 48 is. When men are 49 together for a long period, they begin to feel uneasy. Everyone has little habits of speaking and behaving that are ordinarily acceptable. In the limited space over a long period of time, however, these little habits may become very 50 .
Apparently, although no one wants to be 51 all the time, everyone needs some degree of privacy. When people are enclosed together, they are in what is called a stress situation. That means that they are under an unusual amount of 52 or stress.
People who are well-adjusted are able to 53 stress situations better than others. That is one reason why so much care is taken in 54 our astronauts. These men undergo a long period of testing and training. One of the things tested is their behaviors under stress.
45．A．tired | B．asleep | C．conscious | D．busy |
46．A．So far | B．After all | C．However | D．Therefore |
47．A．long | B．fast | C．dangerous | D．direct |
48．A．fuel | B．entertainment | C．adjustment | D．health |
49．A．shut up | B．held up | C．brought up | D．picked up |
50．A．pleasing | B．annoying | C．common | D．valuable |
51．A．noisy | B．alone | C．personal | D．sociable |
52．A．emphasis | B．conflict | C．power | D．pressure |
53．A．handle | B．create | C．affect | D．investigate |
54．A．becoming | B．choosing | C．ordering | D．promoting |