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 atmosphe

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

admin2010-02-20  78
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 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 reins has been agreed on. The trouble is that it is extremely difficult to be sure about radiation damagea person may feel perfectly well, but the cells of his or her sex organs may be damaged, and this will no be discovered until the birth of deformed children or even grandchildren.
    Missions 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 decrease the damage done by radiation, but no really effective ones have 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 wellprotected space explorers
答案B
解析 该题对应了原文的最后一段。文章说虽然到现在为止还没有报告显示阿波罗号受到辐射损害，但毕竟它登月的时间短。人类能否长时间接受辐射照射还是个未知数。防辐射的药虽然已经研制出来，但只能削减辐射对人类的损害，还谈不上根治。所以说防太空辐射不是容易的事情。
转载请注明原文地址:https://kaotiyun.com/show/Gyt7777K
0

大学英语四级

相关试题推荐
随机试题
最新回复(0)