Radiation Effect Space is a dangerous place, not only because of meteors (流星)but also because of rays from the sun and other

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问题                           Radiation Effect
    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 acts as our protective blanket on earth light, gets through, and this is essential for plants to make the food that we eat. Heat, too, makes our environment endurable. Various kinds of rays come through the air from outer space, but enormous quantities of radiation from the sun are screened off. As soon as men leave the atmosphere they are exposed to this radiation, but their spacesuits or the walls of their spacecrafts, 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" (“雷姆”). Scientists have reason to think that a man can put up with far more radiation than 0.1 rem without being damaged, the figure of 60 reins has been agreed on. The trouble is that it is extremely difficult to be sure about radiation damage-a person may feel perfectly well, but the cells of his or her sex organs may be damaged , and this will not be discovered until the birth of deformed(畸形的)children or even grandchildren. Missions of the Apollo flights have had to cross belts of high radiation and, during the outward and return journeys, the Apollo crew accumulated a larger amount of reins. 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 decrease the damage clone by radiation , but no really effective ones have been found so far.  
We know from the passage that______.

选项 A、exposure to even tiny amounts of radiation is fatal
B、the effect of exposure to radiation is slow in coming
C、radiation is avoidable in space exploration
D、astronauts in spacesuits needn’t worry about radiation damage

答案B

解析 本题考查考生归纳总结文章论点的能力。考的是从文章中我们能够了解的论点。选项A:暴露于数量极小的辐射中也是致命的,这与文章不符,因为第二段第二句话 (Scientists have reason to think that a man can put up with far more radiation than 0.1 rem without being damaged;the figure of 60 rem has been agreed on.)谈到人们能够承受一定量的辐射。选项C:在宇宙探险时可以避开辐射,这也与文章不符,因为文章第二段第一话(Radiation is the greatest known danger to explorers in space.)谈到辐射是宇宙中已知的对探险队员的最大的危险。选项D:穿着宇航服的宇航员不必担心辐射伤害,与文章也不符,第一段最后一句话(As soon as men leave the atmosphere they are exposed to this radiation but their spacesuits or the walls of their spacecrafts,if they are inside,do prevent a lot of radiation damage.)谈到人们穿着宇航服,就会防止很多射线伤害,但并不等于没有伤害。选项B:暴露在射线中的后果要比较长的 时间才看得出来,与文章第二段一致。所以,正确答案是B。
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