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

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

admin2010-10-14  46
问题     Space is 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 which 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 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 put up with far more radiation than 0.1 rem without being damaged; the figure of 60 rems 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 large 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 decrease the damage done by radiation, but no really effective ones been found so far.
It can be inferred from the passage that ______.
选项 A、the Apollo mission was very successful
B、protection from space radiation is no easy job
C、astronauts will have deformed children or grandchildren
D、radiation is not a threat to well-protected space explorers
答案B
解析 本题要求根据文章的内容判断四个选项的推断是否正确。选项A阿波罗计划的成功，选项C宇航员是否一定会有畸形的子孙，在文章中没有提及。文章中说辐射对人体的危害难以确定，而且短期内难以察觉等等，说明离开大气层后人类还没有找到可靠的保护手段，所以选项D“辐射对很好保护的太空探索者没有威胁”是不对的。选项B“太空辐射的防护不是一件容易的事情”符合文章的意思，因此B为正确答案。
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