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 (紫外线的) 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 millirems; it __10__ according toswheresyou 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

    【解析】act as “充当、起……作用”；act for “代表、代理”；act on “按照”。本句意为大气层起到保护伞的作用。

    2.【答案】D

    【解析】be essential for “对……来说是首要的、基础的”，固定搭配。

    3【答案】D

    【解析】本句意为：热不仅使我们的生产环境温度适宜，而且紫外线也能穿透大气。also一般紧跟动词；besides一般用在句前；too可用在句中，用逗号隔开。

    4.【答案】D

    【解析】这里的come through相当于penetrate，穿透。come across “偶遇”；come to “来到”；come from “来自”。本句意为：各类来自外部空间的宇宙射线穿透大气层……，故选come through。

    5.【答案】A

    【解析】as soon as “只要”；as well as “除……之外”；as much as “和……一样多”；as possible as “尽可能的”。

    6.【答案】D

    【解析】do +动词原型的结构表示强调谓语动词。来源：www.examda.com

    7.【答案】C

    【解析】由radiation和explorers可推测，应选space (太空)。本句意为射线是探险者在太空遇见的已知的最大危险。

    8.【答案】A

    【解析】receive表示客观收到；accept表示主观接受。我们受到的辐射并非主观接受。

    9.【答案】D

    【解析】conventional “传统的”；common “共同的、普通的”；general “一般的、总体的”；normal “正常的”。本句意为：我们每年接受的正常辐射量……，故选normal。

    10.【答案】D

    【解析】shift “移动”；convert “转换”；modify “修改”；vary “变化”。根据句意，所处地点不同，所受辐射量也不一样……，故选varies.
Passage 6

As the plane circled over the airport, everyone sensed that something was wrong. The plane was moving unsteadily through the air, and __1__ the passengers had fastened their seat belts, they were suddenly thrown forward.At that moment, the air-hostess __2__ . She looked very pale, but was quite calm. Speaking quickly but almost in a whisper, she __3__ everyone that the pilot hadfainted and asked if any of the passengers knew anything about machines or at __4__ how to drive a car. After a moment hesitation, a man got up and followed the hostesssintosthe pilot cabin.Moving the pilot __5__ , the man took his seat and listened carefully to the urgent instructions that were being sent by radio from the airport __6__ . The plane was now dangerously close to the ground, but to everyone relief, it soon began to climb.The man had to __7__ the airport several times insgroupsto become __8__ with the controls of the plane. But the danger had not yet passed.The terrible __9__ came when he had to land. Followinginstructions, the man guided the plane toward the airfield. It shook violently __10__ it touched the ground and then moved rapidly along the runway and after a long run it stopped safely.

    1. A. although B. while C. therefore D. then

    2. A.showed B. presented C. exposed D. appeared

    3. A.inquired B. insured C. informed D. instructed

    4. A. best B. least C. length D. first

    5. A. back B. aside C. about D. off

    6. A. beneath B. under C. down D. below

    7. A. surround B. circle C. observe D. view

    8. A. intimate B. familiar C. understood D. close

    9. A. moment B. movement C. idea D. affair

    10. A. as B. unless C. while D. so

    1.【答案】A

    【解析】本句意为尽管乘客们都已经系好安全带，他们还是被突然向前抛去。although尽管，引导让步状语从句，符合句意。while当……时候；therefore因此；then接着、然后。

    2.【答案】D

    【解析】show展示、表明；present呈现、陈述，及物动词；expose暴露。appear出现，符合句意。

    3.【答案】C

    【解析】inform通知、告诉，符合句意。inquire询问；insure保险、投保，常与aginst连用；instruct指示、指令。

    4.【答案】B

    【解析】at best最多、至多；at least至少；at length详细地；at first开始、最先。at least最符合句意。

    5.【答案】B

    【解析】本句意为把飞行员挪到一边。aside意为一边、旁边，符合句意。back向后；about到处；move off指车辆启程。

    6.【答案】D

    【解析】beneath和under为介词，后面必需接名词。down向下地，副词。below在下方地，副词，符合句意。

    7.【答案】B

    【解析】surround包围；circle盘旋；observe观察；view认为。此处选择circle，最符合句意。

    8.【答案】B

    【解析】be familiar with为固定搭配，意为熟悉，排除其他选项。

    9.【答案】A

    【解析】根据句意推断，空格处所填词应与when he had做同位语，故moment符合句意。movement运动，idea想法，affair事件。

    10.【答案】A

    【解析】as当……的时候，符合句意。unless除非。while当……时候，它引导的从句动作时间比as引导从句动作的时间要长。So因此，表结果，不符合句意