2. 外语
  3. Space is a dangerous place, not only because of meteors(流星)but also because of rays from the sun and other stars. The atmosphere

Space is a dangerous place, not only because of meteors(流星)but also because of rays from the sun and other stars. The atmosphere

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问题     Space is a dangerous place, not only because of meteors(流星)but also because of rays from the sun and other stars. The atmosphere again【S1】______as our protective blanket on earth. Light gets Light, and this is essential for plants to make the food which we eat. Heat ,too, makes our environment【S2】______. Various  kinds of rays come through the air from outer space ,but enormous【S3】______of radiation from the sun are【S4】______off. As soon as men leave the atmosphere they are【S5】______to this radiation but their spacesuits or the walls of their spacecraft ,if they are inside ,do prevent a lot of radiation damage.
    Radiation is the greatest known danger to explorers in space. The unit of radiation is called "rem". Scientists have reason to think that a man can【S6】______up with far more radiation than 0.1 rem without being  damaged; the figure of 60 rems has been【S7】______on. The trouble is that it is extremely difficult to be sure about radiation damage -- a person may feel perfectly well ,hut the cells of his or her sex organs may he  damaged, and  this  will  not  be  discovered  until  the  birth  of【S8】______children  or  even grandchildren.【S9】______of the Apollo flights have had to cross belts of high amount of rems. So far, no dangerous amounts of radiation have been reported, but the Apollo missions have been quite short. We simply do not know yet how men are going to get on when they spend weeks and months outside the protection of the atmosphere, working in a space laboratory. Drugs might help to【S10】______the damage done by radiation, but no really effective ones have been found so far.

A)missions               B)acts                             C)decay
D)quality                E)quantities                       F)shelter
G)screened               H)deformed                         I)increase
J)agreed                 K)endurable                        L)exposed
M)behaves                N)decrease                         O)put
【S9】
选项
答案A
解析 空缺部分充当句子的主语，其意思应该是“使命”或“任务”，并且应该是一个充当主语的名词。 mission 意为“使命，任务”，正好符合这一要求。
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