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 2. Light gets through, and this is essential 3 plants to make the food which we 4. Heat, 5, makes our environments tolerable and some ultraviolet rays(紫外線的) penetrate the 6. Cosmic(宇宙的) rays of various kinds come 7 the air from outer space, but 8 quantities of radiation from the sun are screened off. 9 men leave the atmosphere they are 10 to this radiation; 11 their spacesuits or the walls of their spacecraft, if they are inside, 12 prevent a lot of radiation damage.Radiation is the greatest known danger to explorers in 13. Doses of radiation are measured in 14 called“rems(雷目)”. We all 15 radiation here on earth from the sun, from cosmic rays and from radioactive minerals.The“16”dose of radiation that we receive each year is about two millirems; it 17 according toswheresyou live, and this is a very rough estimate. Scientists have reason to think 18 a man can 19 far more radiation 20 without being damaged; the figure of 60 rems has been agreed.
　　1.A.for B.with C.on D.as

　　2.A.stars B.sun C.earth D.space

　　3.A.with B.from C.under D.for

　　4.A.use B.live C.eat D.get

　　5.A.again B.also C.besides D.too

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

　　7.A.across B.to C.from D.through

　　8.A.valid B.enormous C.various D.proper

　　9.A.As soon as B.As well as 　C.As much as D.As possible as

　　10.A.shown B.exposed C.faced D.covered

　　11.A.but B.because C.so D.so that

　　12.A.get B.make C.have D.do

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

　　14.A.pieces B.units C.parts D.elements

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

　　16.A.conventional B.common

C.general D.normal

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

　　18.A.what B.which C.that D.why

　　19.A.put up with B.keep up with

　　 C.come up with D.catch up with

　　20.A.from B.than C.as D.away

答案及解析：

　　1. D act as“充當(dāng)、起……作用”；act for“代表、代理”；act on“按照”。本句意為大氣層起到保護(hù)傘的作用。

　　2. C 見上題分析。

　　3. D be essential for“對(duì)……來說是首要的、基礎(chǔ)的”，固定搭配。

　　4. C 只有eat與先行詞food和定語從句which we…搭配。

　　5. D 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(dòng)詞；besides一般用在句前；too可用在句中，用逗號(hào)隔開。

　　6. C 根據(jù)上題所講，penetrate這個(gè)動(dòng)詞后面應(yīng)接atmosphere“大氣”這個(gè)名詞。

　　7. D 這里的come through相當(dāng)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。

　　8. B Valid有效的；various各種各樣的；proper合適的。在四個(gè)選項(xiàng)中只有enormous表示“大量的”意思。

　　9. A 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”。

　　10. B be exposed to“暴露于”，show“展示”；face“面對(duì)”。

　　11. A 本句前半句的意思是：“人們一離開大氣層就會(huì)接觸射線”；后半句意思是：“他們的太空服和太空船會(huì)阻止射線造成的損害”。前后應(yīng)該是轉(zhuǎn)折關(guān)系，故用but。

　　12. D Do +動(dòng)詞原型的結(jié)構(gòu)表示強(qiáng)調(diào)謂語動(dòng)詞。

　　13. C 由radiation和explorers可推測，應(yīng)選space(太空)。本句意為射線是探險(xiǎn)者在太空遇見的已知的危險(xiǎn)。

　　14. B unit“單位、單元”；element“元素”；part“部分”；piece“碎片”本句意為：射線的多少可以以雷目這個(gè)測量單位測量。

　　15. A 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。

　　16. D 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。

　　17. D shift“移動(dòng)”；convert“轉(zhuǎn)換”；modify“修改”；vary“變化”。根據(jù)句意，所處地點(diǎn)不同，所受輻射量也不一樣……，故選varies.

　　18. C 本句應(yīng)填入引導(dǎo)賓語從句的代詞，而從句不缺少主語和賓語，因而不選擇what和which，又加之主句是陳述語氣，故選擇that。

　　19. A put up with“忍受”，固定搭配。keep up with和catch up with意為跟上,come up with意為提出。

　　20. B more (radiation)后應(yīng)加than。