Passage 5

    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 __1__ our protective blanket on earth. Light gets through, and this is essential __2__ plants to make the food which we eat. Heat, __3__ , makes our environments tolerable and some ultraviolet rays (紫外線的) penetrate the atmosphere. Cosmic (宇宙的) rays of various kinds come __4__ the air from outer space, but a great quantity of radiation from the sun are screened off. __5__ men leave the atmosphere they are exposed to this radiation; but their spacesuits or the walls of their spacecraft, if they are inside, __6__ prevent a lot of radiation damage. Radiation is the greatest known danger to explorers in __7__ . Doses of radiation are measured in units called “rems (雷目)”. We all __8__ radiation here on earth from the sun, from cosmic rays and from radioactive minerals. The “__9__” dose of radiation that we receive each year is about two milligrams; it __10__ according to where you live, and this is a very rough estimate.

    1. A. for B. with C. on D. as

    2. A. with B. from C. under D. for

    3. A. again B. also C. besides D. too

    4. A. across B .to C. from D. through

    5. A. As soon as B. As well asC. As much as D. As possible as

    6. A. get B. make C. have D. do

    7. A. earth B. atmosphere C. space D. environment

    8. A. receive B. accept C. bring D. catch

    9. A. conventional B. commonC. general D. normal

    10. A. shifts B. converts C. modifies D. varies

    1.【答案】D （北京安通學(xué)校提供）

    【解析】act as “充當、起……作用”；act for “代表、代理”；act on “按照”。本句意為大氣層起到保護傘的作用。

    2.【答案】D

    【解析】be essential for “對……來說是首要的、基礎(chǔ)的”，固定搭配。

    3【答案】D

    【解析】本句意為：熱不僅使我們的生產(chǎn)環(huán)境溫度適宜，而且紫外線也能穿透大氣。also一般緊跟動詞；besides一般用在句前；too可用在句中，用逗號隔開。

    4.【答案】D

    【解析】這里的come through相當于penetrate，穿透。come across “偶遇”；come to “來到”；come from “來自”。本句意為：各類來自外部空間的宇宙射線穿透大氣層……，故選come through。

    5.【答案】A

    【解析】as soon as “只要”；as well as “除……之外”；as much as “和……一樣多”；as possible as “盡可能的”。

    6.【答案】D

    【解析】do +動詞原型的結(jié)構(gòu)表示強調(diào)謂語動詞。

    7.【答案】C

    【解析】由radiation和explorers可推測，應(yīng)選space (太空)。本句意為射線是探險者在太空遇見的已知的最大危險。

    8.【答案】A

    【解析】receive表示客觀收到；accept表示主觀接受。我們受到的輻射并非主觀接受。

    9.【答案】D

    【解析】conventional “傳統(tǒng)的”；common “共同的、普通的”；general “一般的、總體的”；normal “正常的”。本句意為：我們每年接受的正常輻射量……，故選normal。

    10.【答案】D

    【解析】shift “移動”；convert “轉(zhuǎn)換”；modify “修改”；vary “變化”。根據(jù)句意，所處地點不同，所受輻射量也不一樣……，故選varies