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

游客2023-07-16  20

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. [br] 【C3】

选项 A、with
B、from
C、under
D、for

答案 D

解析 惯用搭配题,be essential for 意为“对…来说是首要的,基础的”,是惯用搭配,所以D正确,考点 essential 意为“必需的,基本的,本质的”,词义比necessary 更强,也更郑重,就事物的本质而言,含义比较绝对,如:It is essential for us to try to decide whether television is a blessing or a curse.我们有必要来评判电视到底是福还是祸
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