托福-练习二十九

1、托福-练习二十九(总分：26.00 ,做题时间：90分钟)一、BPassage 1/B(总题数：2，分数：4.00)1.LIFE EXPECTANCY1 The greatest demographic story of the twentieth century was the enormous increase in life expectancy, the average number of years a person can expect to live. In most modern societies, life expectancy rose dramatically, fro

2、m about 47 years in 1900 to about 76 years in 2000. This does not mean, however, that people suddenly died on their forty- seventh birthday in 1900. It means that if half of the people born in 1900 died in childhood and the rest lived 95 years, theaverage age at death was around 47. The data for 190

3、0 reflect high infant and childhood mortality rates. At that time, surviving the first fifteen years of life was the key to living to old age.Over the century, several factors increased life expectancy, most notably improvements in public health, such as pasteurized milk, sewers, and indoor plumbing

4、. Advances in medical practice, including the use of antibiotics and vaccinations for childhood illnesses, made it increasingly likely that infants would reach adulthood.2 On the one hand, increased life expectancy is a sign of societal well being; on the other hand, an aging population poses its ow

5、n set of problems. Large numbers of elderly, many with chronicdiseases, become a burden on the health care system and on their families. In societies where care of the elderly is a family responsibility, adult children caring for aging parents experience great personal and financial stress.1. An int

6、roductory sentence for a brief summary of the passage is provided below. Complete the summary by selecting the THREEanswer choices that express the most important ideas in the passage. Some sentences do not belong in the summary because they express ideas that are not presented in the passage or are

7、 minor ideas in the passage.This questi on is worth 2 poin ts.*« A. Around half of the population died on their forty-seventh birthday in 1900.* B. The average number of years a person could expect to live rose from 47 to 76 in onlya century.«C. The leading causes of death in 1900 were epi

8、demic diseases.* D. Mortality rate is the number of deaths in a period as a proportion of the entire population.* E. Improvements in public health and medical practices significantly raised life expectancy.* F. An aging population increases the stress on a society's health care system and on fam

9、ilies.ABCDEFBEFKey information: .life expectancy, the average number of years a person can expect to live., rose dramatically, from about 47years in 1900 to about 76years in 2000; .several factors increased life expectancy, most notably improvements in public health.Advances in medical practice.; La

10、rge numbers of elderly, many with chronic diseases,become a burden on the healthcare system and on their families. Answer (A) is inaccurate; answers (C) and (D) are not mentioned.（分数：2.00 ）(1) .LIFE EXPECTANCY1 The greatest demographic story of the twentieth century was the enormous increase in life

11、 expectancy, the average number of years a person can expect to live. In most modern societies, life expectancy rose dramatically, from about 47 years in 1900 to about 76 years in 2000. This does not mean, however, that people suddenly died on their forty- seventh birthday in 1900. It means that if

12、half of the people born in 1900 died in childhood and the rest lived 95 years, theaverage age at death was around 47. The data for 1900 reflect high infant and childhood mortality rates. At that time, surviving the first fifteen years of life was the key to living to old age.Over the century, severa

13、l factors increased life expectancy, most notably improvements in public health, such as pasteurized milk, sewers, and indoor plumbing. Advances in medical practice, including the use of antibiotics and vaccinations for childhood illnesses, made it increasingly likely that infants would reach adulth

14、ood.2 On the one hand, increased life expectancy is a sign of societal well being; on the other hand, an aging population poses its own set of problems. Large numbers of elderly, many with chronicdiseases, become a burden on the health care system and on their families. In societies where care of th

15、e elderly is a family responsibility, adult children caring for aging parents experience great personal and financial stress.1. An introductory sentence for a brief summary of the passage is provided below. Complete the summary by selecting the THREEanswer choices that express the most important ide

16、as in the passage. Some sentences do not belong in the summary because they express ideas that are not presented in the passage or are minor ideas in the passage.This questi on is worth 2 poin ts.* A. Around half of the population died on their forty-seventh birthday in 1900.« B. The average nu

17、mber of years a person could expect to live rose from 47 to 76 in only a century.* C. The leading causes of death in 1900 were epidemic diseases.«D. Mortality rate is the number of deaths in a period as a proportion of the entirepopulation.* E. Improvements in public health and medical practice

18、s significantly raised life expectancy.* F. An aging population increases the stress on a society's health care system and onfamilies.(分数:1.00 )A.B. VC.D.C. VD. V解析： Key information: .life expectancy, the average number of years a person can expect tolive., rose dramatically, from about 47years

19、in 1900 to about 76years in 2000; .several factorsincreased life expectancy, most notably improvements in public health.Advances in medical practice.; Large numbers of elderly, many with chronic diseases, become a burden on the health care system and on their families. Answer (A) is inaccurate; answ

20、ers (C) and (D) are not mentioned. .ARTISTS' USE OF OIL AND ACRYLIC PAINTS1 The oil technique for painting on canvas is superior to other methods mainly because of its great flexibility and ease of manipulation, as well as the wide range of effects that can beproduced. Colors do not change to an

21、y great extent on drying, which means thatthecolor the artistputs down is, with only slight variation, the color desired in the finished work. The artist is free to combine transparent and opaque effects in the same painting. However,theprincipaldefectof oil painting is the darkening of the oil over

22、 time, but this may be reducedby using the highestquality materials.2 The most widely used artists' colors based on the synthetic resins are made by dispersing pigmentin acrylic emulsion. Acrylicpaints are thinned with water, but when they dry, the resin particlescoalesce to form a tough film th

23、at is impervious to water. Acrylic colors may be made mat or glossy and can imitate most of the effects of other water-based colors. They are a boon to painters with a high rate of production because a painting can be completed in one session that might have taken days in oil because of the drying t

24、ime required between layers of paint.3 Acrylic colors are not a complete substitute for oil paints, and artists whose styles require the special manipulative properties of oil colors-including delicacy in handling or smoothly blended tones-find that these possibilities are the exclusive properties o

25、f oils. Althoughpainting in acrylics has certain advantages over painting in oils, the latter remains the standard because the majority of painters find that its advantages outweigh its defects and that in optical quality oil paints surpass all others.2. Select the appropriate sentences from the ans

26、wer choices and match them to the type of paint that they describe. TWO of the answer choices will NOT be used. This question is worth 3 points.Answer ChoicesA. They appear transparent on paper.B. The colors can be thinned with water.C. They allow for smoothly blended tones.D. The paints are applied

27、 to wet plaster.E. They are the preferred paints among artists.F. They have a relatively fast drying time.G. The colors will eventually darken.（分数：1.00 ）A.B.C. VD.D. VF.E. V解析：Oil paints: .special manipulative properties of oil colors.smoothly blended tones.; . the latter remains the standard becaus

28、e the majority of painters find., that in optical quality oil paints surpass all others; . the principal defect of oil painting is the darkening of the oil over time B, F Acrylic paints: Acrylic paints are thinned with water.; .a painting canbe completed in one session that might have taken days in

29、oil because of the drying time requiredAnswers (A) and (D) are not mentioned.WORLD CLIMATIC PATTERNS1 Climate is the general pattern of atmospheric conditions, seasonal variations, and weather extremes in a region over a period of decades. Onemajor factor determining the uneven patterns of world cli

30、mates is the variation in the amount of solar energy striking different parts of the earth. The amount of incoming solar energy reaching the earth's surface varies with latitude, the distance north or south from the equator. Air in the troposphere is heated more at the equator (zero latitude), w

31、here the sun is almost directly overhead, than at the high-latitude poles, where the sun is lower in the sky and strikes the earth at a low angle.2 The large input of heat at and near the equator warms large masses of air. These warm masses rise and spread northward and southward, carrying heat from

32、 the equator toward the poles. At the poles, the warmair becomes cool and falls to the earth. These cool air masses then flow back toward the equator near ground level to fill the space left by rising warm air masses. This general air circulation pattern in the troposphere results in warmaverage tem

33、peratures near the equator, cold average temperatures near the poles, and moderate average temperatures at the middle latitudes.3 The larger input of solar energy near the equator evaporates huge amounts of water from the earth's surface into the troposphere. As the warm, humid air rises, it coo

34、ls rapidly and loses most of its moisture as rain near the equator. The abundant rainfall and the constant warmtemperatures near the equator create the world's tropical rain forests.4 Two major factors cause seasonal changes in climate. One is the earth's annual orbit around the sun; the oth

35、er is the earth's daily rotation around its tilted axis, the imaginary line connecting the two poles. When the North Pole leans toward the sun, the sun's rays strike the Northern Hemisphere more directly per unit of area, bringing summerto the northern half of the earth. At the same time, th

36、e South Pole is tilted away from the sun; thus, winter conditions prevail throughout the Southern Hemisphere. As the earth makes its annual rotation around the sun, these conditions shift and cause a change of seasons.5 As the earth spins around its axis, the general air circulation pattern between

37、the equator and each pole breaks into three separate belts ofmovi ng air, or prevaili ng surface win ds, which affect the distribute nof precipitation over the earth.(分数：2.00)(1) .Select the appropriate sentences from the answer choices and match them to the locationthatthey describe. TWO of the ans

38、wer choices will NOT be used.This questi on is worth 3 poin ts.Answer ChoicesA. Solar energy strikes the earth at a low angle.B. Average annual temperatures are moderate.C. The large input of solar energy heats great masses of air.D. A large quantity of water evaporates into the atmosphere.E. Warm a

39、ir cools and sinks to the earth's surface.F. The sun is almost directly overhead.G. There are three belts of prevailing surface winds.(分数:1.00 )A.B.C. VD. VE.E. VG.解析： At the equator: The large input of heat at and near the equator warms large masses of air; . near the equator evaporates huge am

40、ounts of water from the earth "s surface into the troposphere; .at the equator (zero latitude), where the sun is almost directly overhead.A, E At the poles: .at the high-latitudepoles, where the sun is lower in the sky and strikesthe earth at a low angle; At the poles, the warm air becomes cool

41、 and falls to the earth. Answers (B) and (G) are inaccurate for both the equator and the poles.(2) .An introductory sentence for a brief summary of the passage is provided below. Complete thesummary by selecting the THREEanswer choices that express the most important ideas in the passage. Some sente

42、nces do not belong in the summary because they express ideas that are not presented in the passage or are minor ideas in the passage. This question is worth 2 points.* A. The variation in the amount of solar energy reaching different parts of the earth has a great influence on global climate.* B. Wa

43、rmair flows from the equator toward both poles, where it cools and then flows back toward the equator, creating a general air circulation.* C. The moisture-holding capacity of air, humidity, increases when air is warmed and decreases when it is cooled.* D. The consistently warm temperatures and heav

44、y rainfall near the equator result in tropical rain forests.* E. The earth's annual circling of the sun and its daily spinning around its axis cause its seasonal changes in climate.* F. The chemical content of the troposphere is another factor determining the earth's average temperatures and

45、 thus its climates.(分数:1.00)A. VB. VC.D.C. VF.解析： Key information:One major factor determining the uneven patterns of world climates is thevariation in the amount of solar energy striking different parts of the earth; .carrying heatfrom the equator toward the poles., the warm air becomes cool.cool a

46、ir masses thenflow back toward the equator. This general air circulation pattern.; Two major factors cause seasonal changes in climate.Oneis the earth's annual orbit around the sun; the other is the earth's dailyrotation around its tilted axis Answers (C) and (F) are not mentioned; answer (D

47、) is a minor idea.、Brassage 2/B(总题数：2，分数:22.00)BLACK HOLES1 Nothing in the history of modern astronomy has excited as much speculati on as the object, or eve nt, known as a black hole. Black holeshave provided endless imaginative Ufodder/U for scienee fiction writers and en dless theoretical Ufodder

48、/U for astrophysicists.They are one of the more exotic mani festati ons of the theory of gen eral relativity, and their fascinationlies in the way their tremendous gravityaffects n earby space and time.2 A black hole is very simple in structure: it has a surface-the eve nt horizon-and a center-the s

49、ingularity. Everything else is gravity. The standard model for the formation of a black hole invoIves the collapseof a large star. The imaginary spherical surface surrounding the collapsed star is the eve nt horiz on-an artificial boun dary in space that marks a point of no return. Outside the eve n

50、t horiz on, gravity is stro ng but Ufinite/U, and it is possible for objects to break free of its pull. However, once withi n the eve nt horiz on, an object would n eed to travel faster than light to escape.3 For extremely massive stars, the exclusi on prin ciple-the resista nee between the molecula

51、r particles within the star as they are compressed-will not be stro ng eno ugh to offset the gravity gen erated by the star's own mass. The star's increasing density will overwhelm the exclusi on prin ciple. What follows is Uru naway/U gravitati onal collapse. With no internalforce to stop i

52、t, the star will simply continue to collapse in on itself. Once a collapsing star has contracted throughits eve nt horiz on, nothing can stop it from collaps ing further un til its entire massis crushed down to a single point-a point of infinite density and zero volume-the sin gularity.4 The star no

53、w disappears from the perceivable uni verse, like Uacartoon character/U that jumps into a hole and pulls the hole in after him. UWhat this process leaves behind is a different kind of hole-a profound disturbanee in space-time, a region where gravity is so intense that nothing can escape from it/U. A

54、ny object falli ng within the boun dary of a black hole has no choice but to move in ward toward the sin gularity and disappear from our uni verse forever. Moreover, a black hole can never be plugged up or filled in with matter; the more matter that is poured into a black hole, the bigger it gets.5

55、What would happen to objects, such as astronauts, as they vanished into a black hole? Physicists have been amusing themselves with this question for years, and most believe that the intense gravitati onal forces wouldrip apart the astronauts long before they were crushed at the singularity. Theoreti

56、cally, any astr on auts who man aged to survive the passage would encoun ter some very stra nge thi ngs. For in sta nee, they would experie nee acute time distortion, which would enable them to know, in a few brief sec on ds, the en tire future of the uni verse.6 In side a black hole, space and time

57、 are so warped that the dista nee from the eve nt horiz on to the sin gularity is not a dista nee in space in theno rmal sense that we can measure in kilometers. In stead, it becomes a dista nee in time. The time it takes to reach the sin gularity from the eve nt horiz on-as measured by some one fal

58、li ng in-is proporti onal to the mass of the black hole.7 The only way that astr on auts would know whether they had crossed theeve nt horiz on would be if they tried to halt their fall and climb out aga in by firing their engines eno ugh to push themselves back from the een ter of the hole. However, because of the time warp, if the astr on auts tried to do this, they would reach the singularityfaster than if they had lefttheir engines off. Moreover, sin