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

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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 acts 【C1】______ our protective blanket on 【C2】______ . Light gets through, and this is essential 【C3】______ plants to make the food which we 【C4】______ . Heat, 【C5】______ , makes our environments tolerable and some ultraviolet rays (紫外线) penetrate the 【C6】______ . Cosmic (宇宙的) rays of various kinds come 【C7】______ the air from outer space, but 【C8】______ quantities of radiation from the sun are screened off. As 【C9】______ as men leave the atmosphere they are 【C10】______ to this radiation; 【C11】______ their spacesuits or the walls of their spacecraft, if they are inside, 【C12】______ prevent a lot of radiation damage.
    Radiation is the greatest known danger to explorers in 【C13】______ . Doses of radiation are measured in 【C14】______ called "rems (雷姆)". We all 【C15】______ radiation here on earth from the sun, from cosmic rays and from radioactive minerals. The" 【C16】______ "dose of radiation that we receive each year is about 100 millirems; it 【C17】______ according to where you live, and this is a very rough estimate. Scientists have reason to think 【C18】______ a man can 【C19】______ up with far more radiation
     【C20】______ this without being damaged; the figure of (60) rems has been agreed.
【C14】
选项 A、pieces
B、units
C、parts
D、elements
答案B
解析 词义辨析题，piece 意为“碎片”，unit 意为“单位，单元”，part 意为“部分”，element 意为“元素”，本句的意思是“射线的多少是以雷姆这个 ______来测量的”结合下文可知，“雷姆”是一个度量单位，所以B正确
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大学英语四级

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