2. 职称英语
  3. Space is a dangerous place, not only because of meteors(流星) but also becaus

Space is a dangerous place, not only because of meteors(流星) but also becaus

游客2023-11-18  74
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 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 have been found so far. [br] 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 推断题。文章第一段中指出宇航服及宇航船不能为宇航员挡住所有的辐射，第二段中指出辐射对人体造成的危害程度很难确定，因为宇航员在接受太空辐射后虽自我感觉良好，但却可能在其第一代甚至第二代后代身上出现畸形，而且文章最后指出抵制太空辐射的真正的有效药目前尚未发现，由此可见，“保护人体不受太空辐射是一项不容易的工作”。
转载请注明原文地址:http://tihaiku.com/zcyy/3196622.html
相关试题推荐
随机试题
最新回复(0)