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

游客2024-02-14  15

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 rays of various kinds come【C7】______the air from outer space, but【C8】______quantities of radiation from the sun are screened off.【C9】______  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" (雷目). 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 two 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】______far more radiation【C20】______without being damaged;  the figure of 60 rems has been agreed. [br] 【C14】

选项 A、pieces
B、units
C、parts
D、elements

答案 B

解析 unit“单位、单元”;element“元素”;part“部分”;piece“碎片”,本句意思是:“射线的多少可以以雷目这个测量单位测量”。
转载请注明原文地址:https://tihaiku.com/zcyy/3451399.html
最新回复(0)