上海对外贸易学院

2011年攻读硕士学位研究生入学考试

《翻译硕士英语》试题

适用翻译硕士专业

Note: Write all your answer on the answer sheet. Your answers written on this paper will not be scored.

I．Vocabulary and Grammar (20 points)

1.Heavily perfumed white flowers, such as gardenias, were favorites

with collectors in the eighteenth century, when __ was valued

much more highly than it is today.

a.scent

b. beauty

c. elegance

d. color

2.He would have finished his college education, but he ___to quit

and find a job to support his family.

a.had had

b. has

c. had

d. would have

3.Had Judy been more careful on the maths exam, she ___much

better results now.

a.would be getting

b.could have got

c.must get

d.would get

4.The travelers sought shelter ____the rain and happened to find a

road-side inn.

a. from

b. against

c. for

d. with

5.While walking along the icy river banks, we could see cracks in

the ice ___ in all directions.

a. radiating

b. dividing

c. splitting

d. tearing

6.This instrument can ___ the temperature of the room as you

please.

a. modify

b. stabilize

c. regulate

d. normalize

7.The payment that the motorist will have to make will be ___ to the

amount of damage he has done to the other person's car.

a. related

b. relevant

c. proportional

d. consistent

8.Sometimes the student may be asked to write about his ___ to a

certain book or article that has some bearing on the subject being studied.

a. comment

b. reaction

c. impression

d. comprehension

9.In ___ of your bad work I regret to tell you that I am forced to

dismiss you.

a. respect

b. consequence

c. spite

d. case

10.H is description of the event ____ to the truth but there were a few

inaccuracies.

a. approximated

b. amounted

c. came

d. approached

11.B reak ing Mary’s doll was purely ___ ; John did not mean to do it.

a. accidental

b. inevitable

c. unavoidable

d. natural

12.A fter riding such a long way on a bicycle, his bottom was very

___.

a. sensitive

b. tender

c. uncomfortable

d. tough

13.T his advertisement is ___ to attract much attention.

a. assigned

b. calculated

c. defined

d. contributed

14.O ur journey was very slow because the train stopped ___ at

different villages.

a. continually

b. continuously

c. gradually

d. unceasingly

15.T o ___ concrete is to embed metal in it to make it stronger.

a. intensify

b. consolidate

c. reinforce

d. empower

16.T hey will take measures to guarantee against the ___ of similar

incidents in the future.

a. appearance

b. expression

c. reflection

d. occurrence

17.I t was a vast stretch of country with cities ___.

a. at first sight

b. in the first place

c. at a distance

d. in the distant

18.S hakespeare is a great writer, poet and dramatist. It'll not be very

easy to find his ___.

a. correspondent

b. peer

c. rival

d. counterpart

19.T he suggestion was ___in a memorandum published here today.

a. composed

b. merged

c. contained

d. absorbed

20.H enry forgot to bring his admission card with him. ___, he was

allowed into the hall to take the examination.

a. Moreover

b. Certainly

c. Nevertheless

d. Consequently

21.___ with you, I have a long way to go.

a.Compared

b. Compering

c. Compare

d. Being compared

22.T he painter lived more than a decade in Europe ___ he could be in

close contact with other masters.

a.where

b.in which

c.that

d. in that

23.M easles ___ a long time to get over.

a. spend

b. spends

c. take

d. takes

24.T he law requires that everyone ___ his car checked at least once a

week.

a. has

b. had

c. have

d. would have

25.T he traveler ___ inexperienced doesn’t know how to plan a trip.

a. to be

b. being

c. is

d.as being

26.T he javelin used in competition must be between 260 and 270

centimeters ___.

a. in length

b. it is long

c. its length

d. length

27.___ usually thought to end in Northern New Mexico, the Rocky

Mountains really extend southward to the frontier of Mexico.

a.Despite

b. To be

c. while

d. however

28.H e talks as if he ____ everything in the world.

a. knows

b. knew

c. had known

d. would have known

29.E very one of the boys___ here yesterday has a bicycle.

a. was

b. were

c. who was

d. who were

30.M odern machinery ____ been installed in this newly built factory.

a. has

b. have

c. is

d. are

31.T he Kentucky Derby __every may at Churchill Downs in

Louisville, Kentucky.

a. to be run

b. run

c. it may be run

d. is run

32.T he farmer uses wood to build a house ___ to store grains.

a. with which

b. where

c. which

d. in which

33.T he sea mammal medusa is popularly called a jellyfish because

it___ jelly.

a. looks rather like

b. looks like rather

c. likes looking rather

d. rather likes looking

34.S cientists stress that the overall warming trend of the last decade

holds much more significance ___ single year's temperatures.

a. any do

b. than do any

c. than any do

d. do than

35.A n ideal is a standard ___ people judge real phenomena.

a.how

b. of

c. by which

d. for it

36.A newspaper's political cartoons___ capsule versions of editorial

opinion.

a. serve as

b. serve

c. in serving

d. be served

37.A mong the giants of the sea ___, which may weigh up to 1,000

pounds.

a. tuna

b. the tuna

c. being the tuna

d. is the tuna

38.A semiconductor is a substance that seldom conducts electricity,

but___ under certain circumstances.

a.so can do

b. do so can

c. can do so

d. so do can

39.U ntil the ninth century, written words were not actually separated,

___in some literary writing, dots or points were used to indicate

divisions.

a. in spite of

b. contrary

c. contrast to

d. but

40.T he closer to one of the Earth's poles, the greater ___ gravitational

force.

a.it

b. the

c. has

d. it has

II．Correct the one mistake in each of the following sentences. (20 points)

1.Rather than waste of time in traffic as they try to reach city center

venues, business people are using conference facilities on the offer at airports.

2.When Tom heard his name, his legs were so weak he could only

hardly stand up.

3.Those people will spend significant amount of time in other

countries for seeking new ingredients

4.Things produced on a farm, such as milk, potato, and wool, are

produce.

5.Not long years ago, airports hotels were

uncomfortable , unattractive and inconvenient

6.The president returned with only a few vague worded cultural and

scientific agreements.

7.Such were the predominant land life throughout the Mesozoic age.

8.We put on our mackintoshes to protect us against the rain.

9.On New Year Eve, every member of the club enjoys a

get-together.

10.M ay I be excused for the meeting?

11.T he man denied why he had broken into the house and he had

taken the watch.

12.T he manner where the fuel enters a diesel engine is the primary

factor that affects its efficiency.

13.I think he is quietly honest in his intentions.

14.A ttempting to smuggle drugs into the country, customs officials

apprehended them.

15.T he pupils left the classroom one after the others.

16.Y ale was the second institution of higher learning to be establish

in the countries.

17.A great many educators firmly believe that English is one of the

poorest taught subjects in high school today.

18.W hen I returned home, I found the window open and something

was stolen.

19.B ecause my hands are clean, I have a right to call you account.

20.D emand for small meeting rooms is huge, usually for interview or

one-to-one meetings , where executives fly in and out of the same

day.

III．Reading Comprehension (40 points)

1.

We have known for a long time that the organization of any particular society is influenced by the definition of the sexes and the distinction drawn between them. But we have realized only recently that the identity of each sex is not so easy to pin down, and that definitions evolve in accordance with different types of culture known to us, that is, scientific discoveries and ideological revolutions. Our nature is not considered as immutable, either socially or biologically. As we approach the beginning of the 21st century, the substantial progress made in biology and genetics is radically challenging the roles, responsibilities and specific characteristics attributed to each sex, and yet, scarcely twenty years ago, these were thought to be “beyond dispute”.

We can safely say, with a few minor exceptions, that the definition of the sexes and their respective functions remained unchanged in the West from the beginning of the 19th century to the 1960s. The role distinction, raised in some cases to the status of uncompromising dualism on a strongly hierarchical model, lasted throughout this period, appealing for its justification to nature, religion and customs alleged to have existed since the dawn of time. The woman bore children and took care of the home. The man set out to conquer the world and was responsible for the survival of his family, by satisfying their needs in peacetime and going to war when necessary.

The entire world order rested on the divergence of the sexes. Any overlapping or confusion between the roles was seen as a threat to the time-honored order of things. It was felt to be against nature, a deviation from the norm.

Sex roles were determined a ccording to the “place”appropriate to each. Women's place was, first and foremost, in the home. The outside world, i.e. workshops, factories and business firms, belonged to men. This sex-based division of the world (private and public) gave rise to a strict dichotomy between the attitudes, which conferred on each its special identity. The

woman sequestered at home, “cared, nurtured and conserved”. To do this, she had no need to be daring, ambitious, tough or competitive. The man, on the other hand, competing with his fellow men, was caught up every day in the struggle for survival, and hence developed those characteristics which were thought natural in a man. Today, many women go out to work, and their reasons for doing so have changed considerably. Besides the traditional financial incentives, we find ambition and personal fulfillment motivating those in the most favorable circumstances, and the wish to have a social life and to get out of their domestic isolation influencing others. Above all, for all women, work is invariably connected with the desire for independence.

1.It is only in recent years that we have recognized that

A.there is almost no clue to the identity of both sexes.

B.the role distinction between different sexes is conspicuous.

C.the different definitions of sexes bears on the development of

culture.

D.the progress of civilization greatly influences the role definitions of

sexes.

2.From paragraph 1 we can infer that it is now possible for women to

embark on a career because

A.the change in sex roles is out of the question.

B.women's lib has been going on for many years.

C.ideas about the roles of women have been changing.

D.the expansion of sciences scarcely remolds the women's roles.

3.The author believes that sex discrimination in the West before the

1960s was

A.preferable.

B.prevalent.

C.presumable.

D.precedent.

4.According to the fourth paragraph, the author seems to think that

A. female passivity is natural.

B. men and women are physically identical.

C. men are born competitive and aggressive.

D. some different sex identity is acquired.

5. According to the author, which of the following is the most important

reason for women to go to work?

A.Wish to claim their rights and freedom.

B.Ambition and self-fulfillment.

C.Financial incentives.

D.Desire for a social life.

2.

One great benefit of the Web is that it allows us to move information online that now resides in paper form. Several states in America are using the Web in a profound way. You can apply for various permits or submit applications for business licenses. Some states are putting up listings of jobs—not just state government jobs, but all the jobs available in the state. I believe, over time, that all the information that governments print, and all those paper forms they now have, will be moved on to the Internet.

Electronic commerce notches up month-by-month too. It is difficult to measure, because a lot of electronic commerce involves existing buyers and sellers who are simply moving paperbased transactions to the Web. That is not new business. Microsoft, for example, purchases millions of dollars of PCs online instead of by paper. However, that is not a fundamental change; it has just improved the efficiency of an existing process. The biggest impact has occurred where electronic commerce matches buyers and sellers who would not previously have found each other. When you go to a book site and find an obscure book that you never would have found in a physical bookstore, that is a new type of commerce.

Today, about half of all PCs are still not connected to the Web. Getting communications costs down and making all the software simpler will bring in those people. And that, in turn, will move us closer to the critical mass that will make the Web lifesty le everyone’s lifestyle. One element that people underestimate is the degree to which the hardware and software will improve. Just take one aspect: screen technology. I do my e-mail on a

20-inch liquid crystal display (LCD) monitor. It is not available at a reasonable price yet, but in two years it will be. In ten years, a 20-inch LCD with much higher resolution will be commonplace. The boundary between a television set and a PC will be blurred because even the set-top box that you connect up to your cable or satellite will have a processor more powerful than what we have today in the most expensive PC. This will, in effect, make your television a computer.

Interaction with the Web also will improve, making it much easier for people to be involved. Today the keywords we use to search the Web often return to too many articles to sort through, many of them out of context. If you want to learn about the fastest computer chip available, you might end up getting responses instead about potato chips being delivered in fast trucks. In the future, we shall be either speaking or typing sentences into the computer. If you ask about the speed of chips, the result will be about computers, not potatoes. Speech recognition also means that you will be able to call in on a phone and ask if you have any new messages, or check on a flight, or check on the weather.

To predict that it will take over ten years for these changes to happen is probably pessimistic. We usually overestimate what we can do in two years and underestimate what we can do in ten. The Web will be as much a way of life as the car by 2008.

6. Electronic commerce becomes a new type of commerce

when_____.

A. paperbased transactions are moved on to the Web

B. the efficiency of the existing process is improved by Internet

C. new buyers and sellers find each other on the Internet

D. a book site offers the books several bookstores have altogether

7. The use of computer will be as common as the use of cars

when_____.

A. governments begin to move administration on-line

B. electronic commerce causes a fundamental change

C. computer and communication become simpler and cheaper

D. the boundary between the computer and the TV disappear

8. What is the current problem with the Web according to the passage?

A. Too much information.

B. Lack of response.

C. Ineffective interaction.

D. Slowness of speed.

9. The example of potato chips is used to illustrate_____.

A. the defect of computers at the present stage of development

B. the similarity between a computer chip and a potato chip

C. the richness of information available on the web

D. the irrelevant responses the web sometimes offers

10. The passage is mainly trying to show that_____.

A. the web is becoming a way of conveying information

B. the web will bring about a new way of life

C. electronic commerce develops with the Internet

D. interaction with the Web will become easier

3.

The deep sea typically has a sparse fauna dominated by tiny worms and crustaceans, with an even sparser distribution of larger animals. However, near hydrothermal vents, areas of the ocean where warm water emerges from subterranean sources live remarkable densities of huge clams, blind crabs, and fish.

Most deep-sea faunas rely for food on particulate matter, ultimately derived

from photosynthesis, falling from above. The food supplies necessary to sustain the large vent communities, however, must be many times the ordinary fallout. The first reports describing vent faunas proposed two possible sources of nutrition: bacterial chemosynthesis, production of food by bacteria using energy derived from chemical changes, and advection, the drifting of food materials from surrounding regions. Later, evidence in support of the idea of intense local chemosynthesis was accumulated: hydrogen sulfide was found in vent water; many vent-site bacteria were found to be capable of chemosynthesis; and extremely large concentrations of bacteria were found in samples of vent water thought to be pure. This final observation seemed decisive. If such astonishing concentrations of bacteria were typical of vent outflow, then food within the vent would dwarf any contribution from advection. Hence, the widely quoted conclusion was reached that bacterial chemosynthesis provides the foundation for hydrothermal-vent food chains—an exciting prospect because no other communities on Earth are independent of photosynthesis.

There are, however, certain difficulties with this interpretation. For example, some of the large sedentary organisms associated with vents are also found at ordinary deep-sea temperatures many meters from the nearest hydrothermal sources. This suggests that bacterial chemosynthesis is not a sufficient source of nutrition for these creatures. Another difficulty is that similarly dense populations of large deep-sea animals have been found in the proximity of “smokers”—vents where water emerges at temperatures up to 350℃. No bacteria can survive such heat, and no bacteria were found there. Unless smokers are consistently located near more hospitable

warm-water vents, chemosynthesis can account for only a fraction of the vent faunas. It is conceivable, however, that these large, sedentary organisms do in fact feed on bacteria that grow in warm-water vents, rise in the vent water, and then rain in peripheral areas to nourish animals living some distance from the warm-water vents.

Nonetheless advection is a more likely alternative food source. Research has demonstrated that adjective flow, which originates near the surface of the ocean where suspended particulate matter accumulates, transports some of that matter and water to the vents. Estimates suggest that for every cubic meter of vent discharge, 350 milligrams of particulate organic material would be adverted into the vent area. Thus, for an average-sized vent, advection could provide more than 30 kilograms of potential food per day. In addition, it is likely that small live animals in the adverted water might be killed or stunned by thermal and/or chemical shock, thereby contributing to the food supply of vents.

11. The passage provides information for answering which of the

following questions?

A. What causes warm-water vents to form?

B. Do vent faunas consume more than do deep-sea faunas of

similar size?

C. Do bacteria live in the vent water of smokers?

D. What role does hydrogen sulfide play in chemosynthesis?

12. The information in the passage suggests that the majority of

deep-sea faunas that live in nonevent habitats have which of

the following characteristics?

A. They do not normally feed on particles of food in the water.

B. They are smaller than many vent faunas.

C. They are predators.

D. They derive nutrition from a chemosynthetic food source.

13. The primary purpose of the passage is to

A. describe a previously unknown natural phenomenon

B. reconstruct the evolution of a natural phenomenon

C. establish unequivocally the accuracy of a hypothesis

D. survey explanations for a natural phenomenon and determine

which is best supported by evidence

14. Which of the following does the author cite as a weakness in the

argument that bacterial chemosynthesis provides the

foundation for the food chains at deep-sea vents?

A. Vents are colonized by some of the same animals found in other

areas of the ocean floor.

B. Vent water does not contain sufficient quantities of hydrogen

sulfide.

C. Bacteria cannot produce large quantities of food quickly

enough.

D. Large concentrations of minerals are found in vent water.

15. Which of the following is information supplied in the passage

that would support the statement that the food supplies

necessary to sustain vent communities must be many times that

of ordinary fallout?

I. Large vent faunas move from vent to vent in search of food.

II. Vent faunas are not able to consume food produced by

photosynthesis.

III. Vents are more densely populated than are other deep-sea areas.

A. I only

B. III only

C. I and II only

D. II and III only

4.

Modern technology has put men on the moon and deciphered the human genome. But when it comes to brewing up flu to make vaccines, science still turns to the incredible edible egg. Ever since the 1940s, vaccine makers have grown large batches of virus inside chicken eggs. But given that some 36,000 Americans die of flu each year, it’s remarkable that our first line of defense is still what Secretary of Health and Human Services Tommy Thompson calls “the cumbersome and archaic egg-based production.” New cell-based technologies are in the pipeline, however, and may finally get the support they need now that the United States is faced with a critical shortage of flu vaccine. Although experts disagree on whether new ways of producing vaccine could have prevented a shortage like the one happening today, there is no doubt that the existing system has serious flaws.

Each year, vaccine manufacturers place advance orders for millions of specially grown chicken eggs. Meanwhile, public-health officials monitor circulating strains of flu, and each March they recommend three strains—two influenza A strains and one B strain—for manufacturers to include in vaccines. In the late spring and summer, automated machines inject virus into eggs and later suck out the influenza-rich goop. Virus from the eggs’ innards gets killed and processed to remove egg proteins and other contaminants before being packaged into vials for fall shipment.

Why has this egg method persisted for six decades? The main reason is that it’s reliable. But even though the eggs are reliable, they have serious drawbacks. One is the long lead time needed to order the eggs. That means it’s hard to make more vaccine in a hurry, in case of a shortage or unexpected outbreak. And eggs may simply be too cumbersome to keep up with the hundreds of millions of doses required to handle the demand for flu vaccine.

What’s more, some flu strains don’t grow well in eggs. Last year, scientists were unable to include the Fujian strain in the vaccine formulation. It was a relatively new strain, and manufacturers simply couldn’t find a quick way to adapt it so that it gr ew well in eggs. “We knew the strain was out there,” recalls Theodore of the University of Colorado Health Sciences Center, “but public-health officials were left without a vaccine—and, consequently, a more severe flu season.”

Worse, the viruses that pose the greatest threat might be hardest to grow in eggs. That’s because global pandemics like the one that killed over 50 million people between 1918 and 1920 are thought to occur when a bird influenza changes in a way that lets it cross the species barrier and infect humans. Since humans haven’t encountered the new virus before, they have little protective immunity. The deadly bird flu circulating in Asia in 1997

and 1998, for example, worried public-health officials because it spread to some people who handled birds and killed them—although the bug never circulated among humans. But when scientists tried to make vaccine the

old-fashioned way, the bird flu quickly killed the eggs.

16. The moon-landing is mentioned in the first paragraph to

illustrate_____.

A. technology cannot solve all of our human problems

B. progress in vaccine research for influenza has lagged behind

C. great achievements have been made by men in exploring the unknown

D. the development of vaccine production methods cannot be stopped

17. What step is essential to the traditional production of flu vaccine?

A. Manufacturers implant the vaccine into ordered chicken eggs.

B. Scientists identify the exact strain soon after a flu pandemic starts.

C. Public health measures are taken as an important

pandemic-fighting tool.

D. Viruses are deadened and made clean before being put into vaccine use.

18. The foremost reason why the egg-based method is defective lies

in_____.

A. the complex process of vaccine production

B. its potential threat to human being

C. the low survival rate for new flu vaccines

D. its contribution to the flu vaccine shortage

19. Which of the following is true according to the passage?

A. Flu vaccines now mainly use egg-based technology.

B. A bird influenza has once circulated among humans.

C. Safety can be greatly improved with cell-culture vaccines.

D. Modern vaccine production methods are to replace egg-based methods.

20. In the author’s view, the new vaccine production method seems to be_____.

A. remarkable

B. criticized

C. efficient

D. accepted

5.

Surprisingly enough, modern historians have rarely interested themselves in

the history of the American South in the period before the South began to become self-consciously and distinctively “Southern”—the decades after 1815. Consequently, the cultural history of Britain’s North American empire in the seventeenth and eighteenth centuries has been written almost as if the Southern colonies had never existed. The American culture that emerged during the Colonial and Revolutionary eras has been depicted as having been simply an extension of New England Puritan culture. However, Professor Davis has recently argued that the South stood apart from the rest of American society during this early period, following its own unique pattern of cultural development. The case for Southern distinctiveness rests upon two related premises: first, that the cultural similarities among the five Southern colonies were far more impressive than the differences, and second, that what made those colonies alike also made them different from the other colonies. The first, for which Davis offers an enormous amount of evidence, can be accepted without major reservations; the second is far more problematic.

What makes the second premise problematic is the use of the Puritan colonies as a basis for comparison. Quite properly, Davis decries the excessive influence ascribed by historians to the Puritans in the formation of American culture. Yet Davis inadvertently adds weight to such ascriptions by using the Puritans as the standard against which to assess the achievements and contributions of Southern colonials. Throughout, Davis focuses on the important, and undeniable, differences between the Southern and Puritan colonies in motives for and patterns of early settlement, in attitudes toward nature and Native Americans, and in the degree of receptivity to metropolitan cultural influences.

However, recent scholarship has strongly suggested that those aspects of early New England culture that seem to have been most distinctly Puritan, such as the strong religious orientation and the communal impulse, were not even typical of New England as a whole, but were largely confined to the two colonies of Massachusetts and Connecticut. Thus, what in contrast to the Puritan colonies appears to Davis to be peculiarly Southern—acquisitiveness, a strong interest in politics and the law, and a tendency to cultivate metropolitan cultural models—was not only more typically English than the cultural patterns exhibited by Puritan Massachusetts and Connecticut, but also almost certainly characteristic of most other early modern British colonies from Barbados north to Rhode Island and New Hampshire. Within the larger framework of American colonial life, then, not the Southern but the Puritan colonies appear to have been distinctive, and even they seem to have been rapidly assimilating to the dominant cultural patterns by the late Colonial period.

21. The author is primarily concerned with

A. refuting a claim about the influence of Puritan culture on the early

American South

B. refuting a thesis about the distinctiveness of the culture of the

early American South

C. refuting the two premises that underlie Davis’discussion of the

culture of the American South in the period before 1815

D. challenging the hypothesis that early American culture was

homogeneous in nature

22. The passage implies that the attitudes toward Native Americans that prevailed in the Southern colonies

A. were in conflict with the cosmopolitan outlook of the South

B. derived from Southerners’strong interest in the law

C. were modeled after those that prevailed in the North

D. differed from those that prevailed in the Puritan colonies

23. According to the author, the depiction of American culture during

the Colonial and Revolutionary eras as an extension of New

England Puritan culture reflects the

A. fact that historians have overestimated the importance of the

Puritans in the development of American culture

B. fact that early American culture was deeply influenced by the

strong religious orientation of the colonists

C. failure to recognize important and undeniable cultural differences

between New Hampshire and Rhode Island on the one hand and

the Southern colonies on the other

D. extent to which Massachusetts and Connecticut served as cultural

models for the other American colonies

24. It can be inferred from the passage that the author would find Davis’

second premise more plausible if it were true that

A. Puritan culture had displayed the tendency characteristic of the

South to cultivate metropolitan cultural models

B. Puritan culture had been dominant in all the non-Southern colonies

during the seventeenth and eighteen centuries

C. the communal impulse and a strong religious orientation had been

more prevalent in the South

D. the various cultural patterns of the Southern colonies had more

closely resembled each other

25. The passage suggests that by the late Colonial period the tendency

to cultivate metropolitan cultural models was a cultural pattern that

was

A. dying out as Puritan influence began to grow

B. self-consciously and distinctively Southern

C. spreading to Massachusetts and Connecticut

D. more characteristic of the Southern colonies than of England

6.

The use of heat pumps has been held back largely by skepticism about advertisers’ claims that heat pumps can provide as many as two units of thermal energy for each unit of electrical energy used, thus apparently contradicting the principle of energy conservation. Heat pumps circulate a fluid refrigerant that cycle alternatively from its liquid phase to its vapor phase in a closed loop. The refrigerant, starting as a low-temperature,

low-pressure vapor, enters a compressor driven by an electric motor. The refrigerant leaves the compressor as a hot, dense vapor and flows through a heat exchanger called the condenser, which transfers heat from the refrigerant to a body of air. Now the refrigerant, as a high-pressure, cooled liquid, confronts a flow restriction which causes the pressure to drop. As the pressure falls, the refrigerant expands and partially vaporizes, becoming chilled. It then passes through a second heat exchanger, the evaporator, which transfers heat from the air to the refrigerant, reducing the temperature of this second body of air. Of the two heat exchangers, one is located inside, and the other one outside the house, so each is in contact with a different body of air: room air and outside air, respectively.

The flow direction of refrigerant through a heat pump is controlled by valves. When the refrigerant flow is reversed, the heat exchangers switch function. This flow-reversal capability allows heat pumps either to heat or cool room air. Now, if under certain conditions a heat pump puts out more thermal energy than it consumes in electrical energy, has the law of energy conservation been challenged? No, not even remotely: the additional input of thermal energy into the circulating refrigerant via the evaporator accounts for the difference in the energy equation.

Unfortunately, there is one real problem. The heating capacity of a heat pump decreases as the outdoor temperature falls. The drop in capacity is caused by the lessening amount of refrigerant mass moved through the compressor at one time. The heating capacity is proportional to this mass flow rate: the less the mass of refrigerant being compressed, the less the thermal load it can transfer through the heat-pump cycle. The volume flow rate of refrigerant vapor through the single-speed rotary compressor used in heat pumps is approximately constant. But cold refrigerant vapor entering a compressor is at lower pressure than warmer vapor. Therefore, the mass of cold refrigerant—and thus the thermal energy it carries—is less than if the refrigerant vapor were warmer before compression.

Here, then, lies a genuine drawback of heat pumps: in extremely cold climates—where the most heat is needed—heat pumps are least able to

supply enough heat.

26. What is the primary purpose of the passage?

27. How did the author resolve the question of whether heat pumps run counter to the principle of energy conservation?

28. In the course of a heating season, when the heating capacity of a heat pump would be greatest?

29. When the heat pumps would be used more widely?

30. What is the role of the flow restriction in a heat pump?

IV．Writing(20 points)

Write a composition in about 350 words on the following remark:

Cooperation and Competition