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本書(shū)收錄了對(duì)外經(jīng)濟(jì)貿(mào)易大學(xué)外語(yǔ)學(xué)院“261二外英語(yǔ)”歷年考研真題（注意：部分年份的科目代碼會(huì)有變動(dòng)，各年真題的科目代碼也可能不一樣，具體參見(jiàn)本書(shū)目錄），且全部真題均提供詳細(xì)的答案解析，備考價(jià)值尤為珍貴！

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2001年對(duì)外經(jīng)濟(jì)貿(mào)易大學(xué)外語(yǔ)學(xué)院二外英語(yǔ)考研真題及詳解




Part One: Vocabulary and structure

Directions: In each of the following sentences there is a blank. Below each sentence are four choices marked A, B, C, and D. Decide which one of the four choices is the most suitable for the blank and circle it. (30%)




1. The doctor cured him _____ his strange disease.

A. with

B. of

C. from

D. off

【答案】B查看答案

【解析】句意：醫(yī)生治好了他的怪病。本題考查固定搭配，cure of意為“治愈”。




2. Investors seem to be losing _____ in the car industry.

A. belief

B. confidence

C. trust

D. reliance

【答案】B查看答案

【解析】句意：投資方好像對(duì)汽車行業(yè)逐漸失去了信心。confidence信心。belief相信；信仰。trust信任，信賴。reliance信賴。




3. In spite of the _____ hostility of his colleagues, he went ahead.

A. introductory

B. preparatory

C. initial

D. preliminary

【答案】C查看答案

【解析】句意：盡管同事最初對(duì)他抱有敵意，但他還是繼續(xù)前進(jìn)。initial最初的。introductory引導(dǎo)的，介紹的。preparatory預(yù)備的。preliminary初步的。




4. He is not such a man _____ would have his work half done.

A. whom

B. whom

C. that

D. as

【答案】D查看答案

【解析】句意：他不是一個(gè)在工作上半途而廢的人。本題考查定語(yǔ)從句，當(dāng)先行詞有such修飾時(shí)，定語(yǔ)從句用as來(lái)引導(dǎo)。




5. Radio and television have made it _____ for advertisers to capture the attention of millions of people.

A. probable

B. possible

C. likely

D. capable

【答案】B查看答案

【解析】句意：收音機(jī)及電視機(jī)使得廣告商有可能用這種方法吸引千百萬(wàn)人的注意。本題考查固定句型，make it for possible for…to do，使得某人做什么成為可能。




6. Salt _____ vegetables from decay.

A. preserves

B. reserves

C. protects

D. insures

【答案】A查看答案

【解析】句意：鹽能防止蔬菜腐爛。本題考查固定搭配，A和C均可與from搭配，但protect意為“保護(hù)，保衛(wèi)”，用以表示“保護(hù)或保衛(wèi)某人或某物不受外界的傷害或侵害”，而preserve重在表示“保持某物原有的狀態(tài)”或“使某物保持完好的狀態(tài)”，故應(yīng)選A。




7. He will agree to do what you require _____ him.

A. in

B. of

C. for

D. from

【答案】B查看答案

【解析】句意：他會(huì)同意你對(duì)他的要求。本題考查固定搭配，require of意為“要求”。




8. The child was _____ for getting his shoes and socks wet.

A. corrected

B. suffered

C. scolded

D. complained

【答案】C查看答案

【解析】句意：這孩子因把鞋子和襪子弄濕而挨罵。scold責(zé)罵。correct糾正。suffer遭受。complain抱怨。




9. I haven’t the _____ idea of what you mean.

A. lightest

B. dimmest

C. faintest

D. smallest

【答案】C查看答案

【解析】句意：我一點(diǎn)也不懂你的意思。本題考查固定搭配，haven’t the faintest idea of意為“一點(diǎn)兒也不懂”。




10. In a typhoon, winds _____ speeds greater than 75 miles per hour.

A. obtain

B. attain

C. approach

D. exceed

【答案】C查看答案

【解析】句意：在一場(chǎng)臺(tái)風(fēng)中，風(fēng)速接近每小時(shí)75英里以上。approach接近。obtain獲得。attain達(dá)到，實(shí)現(xiàn)。exceed超過(guò)。




11. The boy, trying to be independent, _____ his father’s offer of help.

A. turned away

B. let down

C. turned down

D. broke away

【答案】C查看答案

【解析】句意：這個(gè)男孩想要獨(dú)立，所以他拒絕了父親的幫助。turn down減小；拒絕。turn away避開(kāi)。let down使失望。break away脫離；放棄。




12. _____ do we go for picnics.

A. Certainly

B. Sometimes

C. Seldom

D. Once

【答案】C查看答案

【解析】句意：我們很少去野餐。本題考查倒裝句，當(dāng)帶有否定意義的副詞位于句首時(shí)，句子應(yīng)倒裝，故應(yīng)選C。




13. Her display of bad temper completely _____ the party.

A. harmed

B. damaged

C. hurt

D. spoilt

【答案】D查看答案

【解析】句意：她的壞脾氣完全掃了晚會(huì)的興。spoil毀掉、糟蹋、破壞某事物的美或趣味等。harm傷害；危害。damage損害，毀壞。hurt使受傷。




14. The completion of the building has been _____ owing to the heavy rain.

A. held back

B. kept down

C. held up

D. kept back

【答案】A查看答案

【解析】句意：大雨阻礙了大樓的竣工。hold back抑制；阻礙。keep down控制；鎮(zhèn)壓。hold up舉起；阻擋。keep back阻止。




15. _____ irritating effect on humans, the use of phenol as general antiseptic has been largely discontinued.

A. What is

B. Where is

C. Since its

D. Because of its

【答案】D查看答案

【解析】句意：由于苯酚對(duì)人體有刺激性作用，它基本上已經(jīng)被停止用作防腐劑了。本句后半部分已經(jīng)是個(gè)完整的句子，故前半部分應(yīng)用作狀語(yǔ)，A，B，C三個(gè)選項(xiàng)后應(yīng)接句子，故選D，做原因狀語(yǔ)。




16. A historical novel may do more than mirror history; _____ future events.

A. it may even influence

B. even influenced

C. may even influence

D. that it may even influence

【答案】A查看答案

【解析】句意：歷史小說(shuō)不僅僅反映歷史，它甚至?xí)绊懳磥?lái)的事件。句中出現(xiàn)了分號(hào)，由分號(hào)連接的部分必是句子，因而填入的答案要使后半部分最終成為完整的句子。




17. Orchestral instruments _____ under the following types: strings, woodwind, brass and percussion.

A. grouped

B. can group

C. can be grouped

D. to be grouped

【答案】C查看答案

【解析】句意：此句有主語(yǔ)而缺謂語(yǔ)動(dòng)詞，orchestral instrument與group之間為被動(dòng)關(guān)系，應(yīng)用被動(dòng)語(yǔ)態(tài)，故選C。




18. All living organisms constantly absorb carbon 14 _____ their existence.

A. out

B. about

C. around

D. throughout

【答案】D查看答案

【解析】句意：所有的生物體一生都在不斷地吸收碳14。throughout one’s life/ existence是固定短語(yǔ)，意為“……的一生中”。




19. People’s expectations of a higher standard of living increase _____.

A. conditions in their community improve

B. since conditions in their improving community

C. conditions in their community improved

D. as conditions in their community improve

【答案】D查看答案

【解析】句意：人們對(duì)更高生活標(biāo)準(zhǔn)的期望隨著社區(qū)環(huán)境的改善而提高。本題考查狀語(yǔ)從句。空格前是一完整的主謂結(jié)構(gòu)的句子，后面缺少的應(yīng)是作狀語(yǔ)的短語(yǔ)或從句，只有D是完整的從句，故選D。




20. Essentially, a theory is an abstract, symbolic representation of _____ reality.

A. what is conceived

B. that is conceived

C. what is conceived to be

D. that is being conceived of

【答案】C查看答案

【解析】句意：在本質(zhì)上，理論是抽象的，這種抽象可以構(gòu)想為現(xiàn)實(shí)的符號(hào)表示。本題考查名詞性從句，what和that均可引導(dǎo)名詞性從句，但that在所引導(dǎo)的從句中不充當(dāng)任何成分，conceive為不及物動(dòng)詞，使用被動(dòng)語(yǔ)態(tài)時(shí)動(dòng)詞不定式應(yīng)還原。




21. The edible tube mushroom _____ a cushion like, moist cap that is light brown or darkish red.

A. which has

B. to have

C. having

D. has

【答案】D查看答案

【解析】句意：這種可食用的管狀蘑菇有一種類似于軟墊、潮濕的蓋子，呈淺褐色或深紅色。此句已給出主語(yǔ)和由定語(yǔ)從句修飾的賓語(yǔ)，缺少謂語(yǔ)動(dòng)詞，只有D可單獨(dú)作謂語(yǔ)。




22. Variables such as individual and corporate behavior _____ nearly impossible for economists to forecast economic trends with precision.

A. make

B. make it

C. making

D. makes it

【答案】B查看答案

【解析】句意：個(gè)人和企業(yè)行為等變量使得經(jīng)濟(jì)學(xué)家?guī)缀醪豢赡芫_地預(yù)測(cè)經(jīng)濟(jì)趨勢(shì)。本題考查it作形式賓語(yǔ)，主語(yǔ)為復(fù)數(shù)，謂語(yǔ)動(dòng)詞用make，因此本題的正確答案為B。




23. Thomas Jefferson’s achievements as an architect rival his contributions _____ a politician.

A. such

B. more

C. as

D. than

【答案】C查看答案

【解析】句意：托馬斯·杰弗遜作為建筑師的成就與他作為政治家的貢獻(xiàn)相匹敵。動(dòng)詞rival(勝過(guò)，匹敵)前后是兩個(gè)相比較的成分achievements(成果)和contributions(貢獻(xiàn))，由于前面的名詞后出現(xiàn)了短語(yǔ)as an architect，故空白處也應(yīng)用as，使前后對(duì)比成分一致。




24. An ideal is a standard _____ people judge real phenomena.

A. how

B. of

C. by which

D. that

【答案】C查看答案

【解析】句意：理想是人們判斷真實(shí)現(xiàn)象的標(biāo)準(zhǔn)。本題考查定語(yǔ)從句，judge by為固定搭配，意為“根據(jù)……做出判斷”，因此本題的正確答案為C。




25. A simple rule for losing weight is to _____ the number of calories that one consumes daily.

A. cut out on

B. cut in on

C. cut under on

D. cut back on

【答案】D查看答案

【解析】句意：減肥的一個(gè)簡(jiǎn)單法則就是減少每天攝入的卡路里。cut back on削減，縮減。cut out on辜負(fù)。cut in on打斷。cut under折賣(mài)。




26. Dick was the only one who knew how to cook because he had _____ in the kitchen when he was a boy.

A. helped about

B. helped up

C. helped with

D. helped out

【答案】D查看答案

【解析】句意：迪克是唯一一個(gè)知道怎么做飯的人，因?yàn)樗〉臅r(shí)候在廚房打過(guò)下手。A和C后應(yīng)接名詞，B意為“把(某人)扶起來(lái)，幫助(某人)往上搬東西”，故應(yīng)選D。




27. Since he has made an apology, I will _____ what I said against him.

A. take away

B. take up

C. take back

D. take out

【答案】C查看答案

【解析】句意：既然他已經(jīng)道歉了，我將收回對(duì)他說(shuō)的話。take back收回；撤銷。take away帶走，拿走。take up拿起；開(kāi)始從事。take out取出；去掉。




28. He pretended to be an Englishman, but his foreign accent gave him _____.

A. away

B. off

C. out

D. up

【答案】A查看答案

【解析】句意：他假裝是英國(guó)人，但他的外國(guó)腔出賣(mài)了他。give away泄露；出賣(mài)。give off發(fā)出（光等）。give out分發(fā)，發(fā)出。give up放棄。




29. All our efforts to persuade her to come and stay with us were of no _____.

A. result

B. avail

C. effect

C. purpose

【答案】B查看答案

【解析】句意：我們所有勸說(shuō)她來(lái)和我們待在一起的努力一點(diǎn)用都沒(méi)有。本題考查固定搭配，be of avail意為“有用的”，故應(yīng)選B。




30. We will accept your check although it is not our normal _____.

A. habit

B. intention

C. thought

D. practice

【答案】D查看答案

【解析】句意：盡管這不是我們的慣例，但我們還是接受您的支票。practice慣例。habit習(xí)慣。intention意圖。thought思想。




Part Two: Cloze

Choose one word from the box bellow for each black. There are more words than necessary. (20%)







Through history man has had to accept the fact (1)______ all living things must die. All living things show the (2)______of aging, which will eventually result (3)______ death. Aging is not a disease, but as a person pasts maturity, the cells of the body and the (4)______ they form do not function as well as they (5)______ in childhood and adolescence. The body provides less protection against disease and is more prone (6)______ accident.

A number of related causes may (7)______ aging. Some cells of the body have a fairly long life, but they are not replaced when they die. As a person ages, the (8)______ of brain cells and muscle cells decreases. (9)______ body cells die and are replaced by new cells. In an aging person the (10)______ cells may not be as visible or as capable of growth as (11)______ of a young person.

Another factor in aging may be changes within the cells (12)______. Some of the protein chemicals in cells are known to change (13)______ age and become less elastic. This is (14)______ the skin of old people wrinkles and hangs loose. This is also the reason why (15)______ people shrink (16)______ height. There may be more chemical changes in the (17)______. Some complex cell chemicals, such as DNA and RNA, store and pass (18)______ information that the cells need. (19)______ may affect this process (20)______ change the information-carrying molecules so that they do not transmit the information as well.

【答案與解析】

1. that

（根據(jù)橫線前后的內(nèi)容可知，該句為同位語(yǔ)從句，故填入that引導(dǎo)同位語(yǔ)從句。）

2. sign

（此處意為：所有的生物都會(huì)體現(xiàn)出變老的跡象，因此填入sign。）

3. in

（根據(jù)橫線前后的內(nèi)容可知，此處意為：這種變老的跡象最終會(huì)導(dǎo)致死亡，result in為固定搭配，意為“導(dǎo)致”，因此填入in。）

4. organs

（根據(jù)橫線前后的內(nèi)容可知，此處填入名詞，由前面的cells可推斷出此處應(yīng)填organs。）

5. did

（根據(jù)橫線前后的內(nèi)容可知，此處是將老年時(shí)期細(xì)胞和器官的運(yùn)作與童年時(shí)期、青少年時(shí)期進(jìn)行對(duì)比，動(dòng)詞為function，由于主語(yǔ)未變，故可用助動(dòng)詞來(lái)代替function，故填入相應(yīng)的過(guò)去形式did。）

6. to

（be prone to為固定搭配，意為“易于……；傾向于……”，故填入to。）

7. cause

（此處意為：許多相關(guān)因素會(huì)導(dǎo)致變老，由causes可知此處應(yīng)填入意為“導(dǎo)致”的動(dòng)詞，故應(yīng)填入cause。）

8. number

（此處意為：腦細(xì)胞和肌肉細(xì)胞的數(shù)量減少，填入number。）

9. Other

（根據(jù)橫線前后的內(nèi)容可知，腦細(xì)胞和肌肉細(xì)胞的數(shù)量減少，而其他細(xì)胞則會(huì)死亡，代之以新的細(xì)胞，故填入Other。）

10. new

（根據(jù)橫線前面的內(nèi)容可知，死亡之后的細(xì)胞會(huì)被新的細(xì)胞代替，由此可推斷出橫線處講的是新細(xì)胞，填入new。）

11. those

（根據(jù)橫線前后的內(nèi)容可知，此處是將老年人的新細(xì)胞與年輕人的新細(xì)胞進(jìn)行比較，橫線處應(yīng)填入代詞，代指新細(xì)胞，且為復(fù)數(shù)，故填入those。）

12. themselves

（此處意為：變老的另一個(gè)因素可能是細(xì)胞自身內(nèi)部的變化，細(xì)胞為復(fù)數(shù)，故填入themselves。）

13. with

（此處意為：細(xì)胞中的一些蛋白質(zhì)化學(xué)物質(zhì)隨著年齡的增長(zhǎng)而改變，變得不那么有彈性，with意為“隨著”。）

14. why

（根據(jù)此句句意，這就是為什么老年人的皮膚松弛且有皺紋，故填入why。）

15. old

（根據(jù)橫線前后的內(nèi)容可知，此處填入形容詞，后面提到身高減少，故可知說(shuō)的是老年人，填入old。）

16. in

（此處意為：在身高方面縮水，故填入in，意為“在……方面”。）

17. cells

（根據(jù)橫線前后的內(nèi)容可知，此處填入名詞，根據(jù)句意，細(xì)胞內(nèi)部可能會(huì)有更多的化學(xué)變化，因此填入cells。）

18. on

（pass on為固定搭配，意為“傳遞”，因此填入on。）

19. Aging

（根據(jù)橫線前后的內(nèi)容可知，此處填入名詞，根據(jù)句意，影響這種過(guò)程的是變老，因此填入Aging。）

20. and

（根據(jù)橫線前后的內(nèi)容可知，此處表并列關(guān)系，填入連詞，連接兩個(gè)動(dòng)詞，因此填入and。）




Part Three: Reading

Directions: In this section you will find four passages. Do the following multiple-choice questions after each passage (50%)




Passage Ⅰ

The word conservation has a thrifty meaning. To conserve is to save and protect, to leave what we ourselves enjoy in such good condition that others may also share the enjoyment. Our forefathers had no idea that human population would increase faster than the supplies of raw materials; most of them even until very recently, had the foolish idea that treasures are “l(fā)imitless” and “inexhaustible”. Most of the citizens of earlier generations knew little or nothing about the complicated and delicate system that runs all through nature, and which means that, as in a living body, an unhealthy condition of our part will sooner or later be harmful to all the others.

Fifty years ago nature study was not part of the school work; scientific forestry was a new idea; timber was still cheap because it could be brought in any quantity from distant woodlands; soil destruction and river floods were not national problem; nobody had yet studied long-term climactic cycles in relation to proper land use; even the word “conservation” had nothing of the meaning that it has for us today.

For the sake of ourselves and those who will come after us, we must now set about repairing the mistakes of our forefathers. Conservation should, therefore, be made a part of everyone’s daily life. “To know about the water table in the ground is just as important to us as a knowledge of the basic arithmetic formulas. We need to know why all watersheds need the protection of plant life and why the naming current of streams and rivers must be made to yield their full benefit to the soil before they finally escape to the sea. We need to be taught the duty of planting trees as well as of cutting them. We need to know the importance of big, mature trees, because living space for most of man’s fellow creatures on this planet is figured not only in square measure of surface but also in cubic volume above the earth. In brief, it should be our goal to restore as much of the original beauty of nature as we can.




l. The author’s attitude towards the current situation in the exploitation of natural resources is _____.

A. critical

B. neutral

C. positive

D. suspicious

2. According to the author, the greatest mistake of our forefathers was that _____.

A. they had no idea about scientific forestry

B. they were not aware of the significance of nature study

C. they had little or no sense of environmental protection

D. they had no idea of how to make good use of raw material

3. It can be inferred from the third paragraph that earlier generations didn’t realize _____.

A. the importance of the proper use of land

B. the value of the beamy of nature

C. the harmfulness of soil destruction and river floods

D. the interdependence of water, soil, and living things

4. To avoid the mistakes of our forefathers, the author suggests that _____.

A. we plant more trees.

B. we return to nature

C. natural sciences be taught to everybody

D. environmental education be directed toward everyone

5. What does the author imply by saying “l(fā)iving space ... is figured ...also in cubic volume above the earth” (Para. 3)?

A. We need to take some measures to protect space.

B. Our living space should be measured in cubic volume.

C. Our living space on the earth is getting smaller and smaller.

D. We must preserve good living conditions for both birds and animals.

【答案與解析】

1. A 由最后一段的第一句可知，作者將先輩的行為視為mistakes，由此可見(jiàn)他對(duì)開(kāi)發(fā)自然資源的當(dāng)前情形持批評(píng)態(tài)度。

2. C 由第一段的“Our forefathers had no idea that human population would increase faster than the supplies of raw materials”可知，我們先輩最大的錯(cuò)誤就是沒(méi)有環(huán)境保護(hù)意識(shí)。

3. D 由第一段的“Most of the citizens of earlier generations knew little or nothing about the complicated and delicate system that runs all through nature…”可知，自然界是一個(gè)整體，事物之間相互依存，某一部分的破壞遲早會(huì)對(duì)其他方面造成危害，但這一點(diǎn)earlier generations并沒(méi)有意識(shí)到，故應(yīng)選D。

4. D 由最后一段的“Conservation should, therefore, be made a part of everyone’s daily life”可知，每個(gè)人都應(yīng)該具有環(huán)保意識(shí)，故應(yīng)選D。




5. D 這句話是說(shuō)地球上除人以外的其他生物的生存空間越來(lái)越小，之前又提到我們應(yīng)該意識(shí)到樹(shù)木的重要性，文章最后一句指出我們應(yīng)該盡可能地恢復(fù)大自然的美，因此這句話暗指我們應(yīng)該為以樹(shù)木為家園的鳥(niǎo)類以及其他動(dòng)物提供更好的生存環(huán)境，故應(yīng)選D。




Passage Ⅱ

The American economic system is organized around a basically private-enterprise, market-oriented economy in which consumers largely determine what shall be produced by spending their money in the marketplace for those goods and services that they want most. Private businessmen, striving to make profits, produce these goods and services in competition with other businessmen; and the profit motive, operating under competitive pressures, largely determines how these goods and services are produced. Thus, in the American economic system it is the demand of individual consumers, couples with the desire of businessmen to maximize profits and the desire of individuals to maximize their incomes, that together determine what shall be produced and how resources are used to produce it.

An important factor in a market-oriented economy is the mechanism by which consumer demands can be expressed and responded to by producers. In the American economy, this mechanism is provided by a price system, a process in which prices rise and fall in response to relative demands of consumers and supplies offered by seller-producers. If the product is in short supply relative to the demand, the price will be bid up and some consumers will be eliminated from the market. If, on the other hand, producing more of a commodity results in reducing its cost, this will tend to incrust the supply offered by seller-producers, which in turn will lower the price and permit more consumers to buy the product. Thus, price is the regulating mechanism in the American economic system.

The important factor in a private-enterprise economy is that individuals are allowed to own productive resource (private property), and they are permitted to hire labor; gain control over natural resources, and produce goods and service for sale at a profit. In the American economy, the concept of private property embraces not only the ownership of productive resources but also certain rights, including the right to determine the price of a product or to make a free contract with another private individual.




6. In Para. 1, “the desire of individuals to maximize their incomes” means _____.

A. Americans are never satisfied with their incomes

B. Americans tend to overstate their incomes

C. Americans want to have their incomes increased

D. Americans want to increase the purchasing power of their incomes

7. The first two sentences in the second paragraph tell us that _____.

A. producers can satisfy the consumers by mechanized production

B. consumers can express their demands through producers

C. producers decide the prices of products

D. supply and demand regulate prices

8. According to the passage, a private-enterprise economy is characterized by _____.

A. private property and rights concerned

B. manpower and natural resources control

C. ownership of productive resources

D. free contracts and prices

9. The passage is mainly about _____.

A. how American goods arc produced

B. how American consumers buy their goods

C. how American economic system works

D. how American businessmen make their profits

【答案與解析】

6. D 整篇文章講的是美國(guó)經(jīng)濟(jì)體系中的供需關(guān)系，第一段提到消費(fèi)者在很大程度上決定了產(chǎn)品的生產(chǎn)傾向，他們?yōu)樽约鹤钕胍纳唐坊蛘叻?wù)花錢(qián)，由此可知the desire of individuals to maximize their incomes指的是消費(fèi)者想要增加他們收入的購(gòu)買(mǎi)力，以獲得最想得到的商品或者服務(wù)。

7. D 由第二段的“…a process in which prices rise and fall in response to relative demands of consumers and supplies offered by seller-producers”可知，價(jià)格因消費(fèi)者的相對(duì)需求和生產(chǎn)商的供給而上漲或下跌，即D選項(xiàng)的“供應(yīng)和需求調(diào)節(jié)價(jià)格”。

8. A 由最后一段可知，私營(yíng)經(jīng)濟(jì)允許個(gè)人享有生產(chǎn)資源，即私有財(cái)產(chǎn)，同時(shí)又允許個(gè)人享有某些特定權(quán)利，故應(yīng)選A。

9. C 文章開(kāi)頭第一句就提到American economic system，由此可知整篇文章是圍繞該主題而展開(kāi)的，故應(yīng)選C，即美國(guó)的經(jīng)濟(jì)體系是如何運(yùn)作的。




Passage Ⅲ

The great advance in rocket theory 40 years ago showed that liquid-fuel rockets were far superior in every respect to the skyrocket with its weak solid fuel, the only kind of rocket then known, However, during the last decade, large solid-fuel rocket with solid fuels about as powerful as liquid fuels have made their appearance and it is a favorite layperson’s question to inquire which one is “better.” The question is meaningless; one might as well ask whether a gasoline or a diesel engine is “better.” It all depends on the purpose. A liquid-fuel rocket is complicated, but it has the advantage that it can be controlled beautifully. The burning of the rocket engine can be stopped completely; it can be ignited when desired. In addition, the thrust can be made to vary by adjusting the speed of the fuel pumps. A solid-fuel rocket, on the other hand, is rather simple in construction, though hard to build when a really large size is desired. But once you have a solid-fuel rocket, it is ready for action at very short notice. A liquid-fuel rocket has to be fueled first and cannot be held in readiness for very long after it has been fueled. However, once a solid-fuel rocket has been ignited, it will keep burning. It cannot be stopped and reignited whenever desired (it could conceivably be stopped and reignited after a pre-calculated time of burning has elapsed) and its thrust cannot be varied. Because a solid-fuel rocket can be kept ready for a long time, most military, missiles employ solid fuels, but human-piloted spaceflight need the fine adjustments that can only be provided by liquid fuel. It may be added that a liquid-fuel rocket is an expensive device; a large solid-fuel rocket is, by comparison, cheap. But the solid fuel, pound per pound, costs about 10 times as much as the liquid fuel. So you have, on the one hand an expensive rocket with a cheap fuel and on the other hand a comparatively cheap rocket with an expensive fuel.




10. The author feels that a comparison of liquid- and solid-fuel rockets shows that _____.

A. neither type is very economic

B. the liquid-fuel rocket is best

C. each type has certain advantages

D. the solid-fuel rocket is best

……

完整資料來(lái)源：弘博學(xué)習(xí)網(wǎng)