托福-25及答案解析.doc

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1、托福-25 及答案解析(总分：118.84，做题时间：90 分钟)一、READING(总题数：0，分数：0.00)二、Set 1(总题数：1，分数：6.00)POPULATION ECOLOGY1 Population ecology is the science that measures changes in population size and composition and identifies the causes of these fluctuationsPopulation ecology is not concerned solely with the human popul

2、ationIn ecological termsa population consists of the individuals of one species that simultaneously occupy the same general arearely on the same resources, and are affected by similar environmental factorsThe characteristics of a population are shaped by its size and by the interactions among indivi

3、duals and between individuals and their environment 2 Population size is a balance between factors that increase numbers and factors that decrease numbersSome factors that increase populations are favorable light and temperature，adequate food supply, suitable habitat, ability to compete for resource

4、s, and ability to adapt to environmental changeFactors that decrease populations are insufficient or excessive light and temperature, inadequate food supply, unsuitable or destroyed habitat, too many competitors for resources, and inability to adapt to environmental change 3 An important characteris

5、tic of any population is its densityPopulation density is the number of individuals per unit, such as the number of maple trees per square kilometer in a countyEcologists can rarely determine population size by actually counting all individuals within geographical boundaries.Instead, they often use

6、a variety of sampling techniques to estimate densities and total population sizesIn some cases，they estimate population size through indirect indicators, such as the number of nests or burrows, or signs such as tracks or droppings 4 Another important population characteristic, dispersion, is the pat

7、tern of spacing among individuals with the populations geographical boundaries.Various species are distributed in their habitats in different ways to take better advantage of food supplies and shelter, and to avoid predators or find preyWithin a populations range, densities may vary greatly because

8、not all areas provide equally suitable habitat, and also because individuals space themselves in relation to other members of the population 5 Three possible patterns of dispersion are clumped, uniform, and randomA clumped dispersion pattern means that individuals are gathered in patches throughout

9、their habitat Clumping often results from the irregular distribution of resources needed for survival and reproductionFor example, fallen trees keep the forest floor moist, and many forest insects are clumped under logs where the humidity is to their 1ikingClumping may also be associated with mating

10、, safety, or other social behaviorCrane flies, for example, swarm in great numbers, a behavior that increases mating chances, and some fish swim in large schools so they are less likely to be eaten by predators 6 A uniform or evenly spaced distribution results from direct interactions among individu

11、als in the populationFor example, regular spacing of plants may result from shading and competition for waterIn animal populations, uniform distribution is usually caused by competition for some resource or by social interactions that set up individual territories for feeding，breeding, or resting 7

12、Random spacing occurs in the absence of strong attraction or repulsion among individuals in a populationOverall, random patterns are rare in nature, with most populations showing a tendency toward either clumped or uniform distribution 8 Populations change in size, structure, and distribution as the

13、y respond to changes in environmental conditionsFour main variablesbirths, deaths, immigration, and emigration determine the rate of change in the size of the population over timeA change in the birth rate or death rate is the major way that most populations respond to changes in resource availabili

14、tyMembers of some animal species can avoid or reduce the effects of environmental stress by emigrating from one area and immigrating to another with more favorable environmental conditions, thus altering the populations dispersion（分数：5.98）(1).Which sentence below best expresses the essential informa

15、tion in the highlighted sentence in paragraph 1?Incorrect choices change the meaning in important ways or leave out essential information AAny species of life can be studied in population ecology BPopulation ecologists care about the future of humanity CThe growth of the human population is a major

16、concern DPopulation ecology does not consider humans worthy of study（分数：0.46）A.B.C.D.(2).According to the passage, which factor might cause the population of a species to decrease in size? AA favorable amount of light and water BAn ability to hide from or defend against predators CA large number of

17、other species competing for food DA greater number of births than deaths（分数：0.46）A.B.C.D.(3).Which of the following is an indirect indicator of a populations density? AThe distribution of food in a given area BThe number of nests in a given area CThe number of births in a given period of time DThe n

18、umber of individuals counted in a given area（分数：0.46）A.B.C.D.(4).The distribution pattern of individuals within a populations geographical boundaries is known as Apopulation ecology Bpopulation density Cpopulation change Dpopulation dispersion（分数：0.46）A.B.C.D.(5).The word range in paragraph 4 is clo

19、sest in meaning to Aterritory Bcontrol Chistory Dshelter（分数：0.46）A.B.C.D.(6).The word patches in paragraph 5 is closest in meaning to Adark places Bfamily groups Cwarm spots Dsmall areas（分数：0.46）A.B.C.D.(7).The word their in paragraph 5 refers to Aresources Btrees Cinsects Dlogs（分数：0.46）A.B.C.D.(8).

20、All of the following are given as reasons for clumping EXCEPT Auneven resource distribution Bterritorial disputes Cmating behavior Dsafety from predators（分数：0.46）A.B.C.D.(9).The phrase set up in paragraph 6 is closest in meaning to Aforbid Bestablish Cincrease Dconceal（分数：0.46）A.B.C.D.(10).Which of

21、the following situations would be most likely to result in a uniform dispersion pattern? ABirds compete for a place to build their nests BFish swim in large schools to avoid predators CWhales develop strong bonds among relatives DElephants form a circle to protect their young（分数：0.46）A.B.C.D.(11).Wh

22、y does the author mention immigration and emigration in paragraph 8? ATo identify factors affecting population dispersion BTo give examples of territorial behavior in animals CTo show that populations balance themselves over time DTo explain why animal populations are uniformly dispersed（分数：0.46）A.B

23、.C.D.(12).Look at the four squares, *, *, *, and*, which indicate where the following sentence could be added to the passageWhere would the sentence best fit? For example, they might estimate the number of black bears in a national park by counting individuals in a few sample plots representative of

24、 the whole park An important characteristic of any population is its density*Population density is the number of individuals per unit, such as the number of maple trees per square kilometer in a county*Ecologists can rarely determine population size by actually counting all individuals within geogra

25、phical boundaries*Instead, they often use a variety of sampling techniques to estimate densities and total population sizes*In some cases, they estimate populaion size through indirect indicators, such as the number of nests or burrows, or signs such as tracks or droppings（分数：0.46）填空项 1:_(13).Read t

26、he first sentence of a summary of the passageComplete the summary by selecting the THREE answer choices that express the most important ideas in the passageSome sentences do not belong in the summary because they express ideas that are not presented in the passage or are minor ideas in the passageTh

27、is question is worth 2 points Population ecology is the science of populations and the factors that influence them _ _ _ Answer ChoicesAA population is affected by its size，density, and dispersion, as well as the relationships among its members BDispersion of individuals in a population may be clump

28、ed, uniform, or random，as determined by environmental and social factors CClumping is related to safety；for example, fish swim in large schools to reduce their chances of being eaten by predators DMost populations have either clumped or uniform distribution because random spacing is rare in nature E

29、Populations change in density and dispersion as they respond to changes in environmental conditions and resource availability. FIf a population has an abundant food supply and a suitable habitat, it will not undergo evolutionary change（分数：0.46）填空项 1:_三、Set 2(总题数：2，分数：5.50)THE HISTORY OF COMMUNICATIO

30、N TECHNOLOGY1 Communication technology influences the ways in which we think about the worldIt changes the things we think about，the symbols we use to form and communicate ideas, and the arenas in which our thoughts developIn the history of communication, there have been many revolutionary technolog

31、ies, among them the printing press in the fifteenth century and electronic media in the nineteenth century 2 The development of writing was a major advancement in the ability to communicate over distances and to preserve information accuratelyWriting conveyed knowledge of the arts and sciences, whic

32、h provided foundations for other areas of investigationHowever, before books and the printing press, written language was limited to a few clay tablets and parchment scrollsIt was not until books became available that writing made a major impactFor centuries，books were rare and expensive because eac

33、h one was handwritten， a process that took several monthsThe printing press with movable type made it possible to produce hundreds of copies of a book in a single day 3 The invention of the printing press in 1450 launched a new era in the technology of communicationThe printing press opened to large

34、 groups of people a body of information that had previously been confined to the educated few. The printing press brought books to the common people, increasing the ranks of the literateRapid expansion of the arts and sciences and the use of printed materials required a higher level of educationEduc

35、ation became a formalized institution, and children earned adulthood by achieving literacyThe proliferation of books and reading changed how people thought and what they thought aboutReading entailed the linear organization of ideas, stimulating abstract thought and reasoningThe ability to read requ

36、ired a significant increase in a persons attention span, resulting in a higher degree of intellectual disciplineHigher rates of literacy led society to a broader，more global perspective 4 Another significant revolution in communication technology began in the nineteenth century with the advent of el

37、ectronic mediaThe invention of the telegraph in 1843 signaled a new era in communication technology, the electronic eraso called because the telegraph used electrical signals to carry information along an electrical wireThe telegraph fed societys growing appetite for immediate access to information，

38、and it provided a foundation for Successive technologies：the telephone in 1876the phonograph in 1878, film and movies in the 1890s, radio in 1919, and television in 1925 5 As with the earliest handwritten books, radio technology was at first restricted to the educated few, scientists and researchers

39、, but later spread to the greater societyBy the 1930s, the middle classes were listening to news, drama, comedy, and musical performances from thousands of miles awayRadio was the first mass broadcast medium and, together with television a few decades later, it was responsible for altering both the

40、pattern and volume of information that flowed into peoples homes 6 The invention of electronic media changed communication more than any other technological event since the development of writingThe spread of electronic media occurred with a speed never seen before，thus intensifying commercial and s

41、ocial interactionThere was a tremendous shift in how people received the information that contributed to their understanding of the worldVoices or pictures could create ideas that appeared authenticmore so than ideas conveyed by the printed wordThe graphic, intensely human nature of electronic media

42、 enhanced the belief that if it was on the air, it had to be true（分数：4.95）(1).In stating that there have been many revolutionary technologies in paragraph 1，the author means that these technologies were very Acomplex Bexpensive Cinfluential Dcontroversial（分数：0.45）A.B.C.D.(2).Which of the following s

43、tatements can be inferred from paragraph 1 about the history of communication? ACertain advances in technology have greatly changed communication BPeople have both loved and feared new developments in technology CWe do not know what people thought about before modern technology DThe history of moder

44、n communication began in the fifteenth century（分数：0.45）A.B.C.D.(3).According to the passage, at what point did writing begin to have a major effect on communication? AWhen alphabets were developed BWhen books became available CWhen education was formalized DWhen the telegraph was invented（分数：0.45）A.

45、B.C.D.(4).The word one in paragraph 2 refers to Aclay tablet Bscroll Cbook Dprinting press（分数：0.45）A.B.C.D.(5).Which sentence below best expresses the essential information in the highlighted sentence in paragraph 3? Incorrect choices change the meaning in important ways or 1 eave out essential info

46、rmation ANumerous people had access to books and education because of the printing press BIt took several people to operate a printing press, so the number of skilled workers grew rapidly CPreviously forbidden books became available to people that could afford a private education DThe printing press

47、 made it possible for books to include more information than ever before（分数：0.45）A.B.C.D.(6).The word proliferation in paragraph 3 is closest in meaning to Astyle Bexpense Ccontrol Dspread（分数：0.45）A.B.C.D.(7).The word signaled in paragraph 4 is closest in meaning to Afollowed Bannounced Cconcluded D

48、delayed（分数：0.45）A.B.C.D.(8).According to the passage, how did the electronic era get its name? AElectronics became a standard subject taught in schools BThe discovery of electrons occurred during the period CWriters of the period predicted the invention of computers DThe technology sent electrical s

49、ignals along electrical wires（分数：0.45）A.B.C.D.(9).All of the following are given as examples of electronic media EXCEPT Athe telegraph Bthe computer Cmovies Dradio（分数：0.45）A.B.C.D.(10).Why does the author compare books with radio technology in paragraph 5? ATo describe the influence of handwritten books on radio BTo expl