1、托福-26 及答案解析(总分：120.50，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：6.50)DEVELOPMENTS IN THE CONSTRUCTION OF TALL BUILDINGS1 Until the nineteenth century, most tall buildings were constructed of load-bearing masonry walls. Masonry walls had to be thick, particularly at the base, to support a b
2、uildings great weight. Stoneworkers built these walls by placing stone upon stone or brick upon brick, adding strength and stability by placing layers of mortar or cement between the stones. Floors and roofs had to be supported by wooden beams, but the major vertical force of buildings was supported
3、 by thick masonry walls. This imposed serious limitations on the number and size of windows. 2 In the 1850s, an alternative was emerging that would eliminate the need for exterior weight-bearing walls: a three-dimensional grid of metal beams and columns. The introduction of metal construction made i
4、t possible to build larger interior spaces with fewer columns than before. The new construction was capable of supporting all the loads to which a building might be subjected, including the vertical forces caused by the weight of the floors and the horizontal forces caused by the wind or earthquakes
5、. 3 The first buildings to depart from the load-bearing wall tradition were iron-framed. Wrought iron, shaped by hammering the heated metal or roiling it under extreme pressure, contains almost no carbon, and when used as floor beams, it can support a great deal of weight. An interior wrought iron s
6、keleton supported all of the hnildings weight. Exterior walls of reinforced concrete acted mainly as weatherproofing.As masonry yielded to concrete, walls that once bore weight evolved into thin curtain walls that would allow more windows. These modifications produced sturdier, lighter, and taller b
7、uildings that quickly became known as skyscrapers. Skyscrapers satisfied the growing need for office space, warehouses, and department stores. Buildings of eight or more stories quickly transformed the city skyline and dominated the central business districts of American cities such as New York, Chi
8、cago, and St. Louis. 4 Skyscrapers differed from previous tall structures with their use of technical innovations such as cast iron and the elevator. The development of cast iron technology, in which molten iron is poured into a mold, made modern plumbing possible. Cast iron pipes, fittings, and val
9、ves could deliver pressurized water to the many floors of tall buildings and drain wastewater out. The invention of the mechanical elevator made it possible to construct even taller buildings. Before the elevator, office buildings were rarely more than four or five stories high. In 1857, the first p
10、assenger elevator equipped with safety brakes prevented the elevator from falling to the basement when a cable broke. The elevator made the upper floors as rentable as the first floor, liberating architecture from dependence on stairways and human muscle. 5 Not only did these innovations have import
11、ant uses in the engineering of tall buildings, but they also erased the traditional architectural distinctions separating the bottom, middle, and top of a building. Architects designed towers that reached to the heavens in a continuous vertical grid. Iron construction established the principle of re
12、petitive rhythms as a natural expression of construction, as well as the idea that buildings could be made of new materials on a vast scale. 6 Construction techniques were refined and extended over the next several decades to produce what architectural historians have called “true skyscrapers,“ buil
13、dings over twenty stories high. The invention of steel was particularly significanti as steel T-beams and I-beams replaced iron in these new structures. Steel weighs less than half as much as masonry and exceeds both masonry and iron in tension and compression strength as well as resistance to fatig
14、ue. Steel rivets replaced iron bolts and were in turn replaced by electric arc welding in the 1920s. The skyscrapers steel skeleton could meet all of the structural requirements while occupying very little interior space. Exterior curtain walls could be quite thin, since their only function now was
15、to let in light and keep the weather out.（分数：6.50）(1).Which of the following was a typical characteristic of tall buildings before the nineteenth century?AStone floors and roofsBThick walls of stone or brickCA large number of tall windowsDAn interior frame of metal（分数：0.50）A.B.C.D.(2).The word force
16、 in paragraph 1 is closest in meaning toAappearanceBshapeCloadDmovement（分数：0.50）A.B.C.D.(3).All of the following are given as benefits of iron-frame construction EXCEPTAsturdy walls made of stone or brickBlarge interior spaces with few columnsCa skeleton that supported heavy loadsDexterior walls wit
17、h many windows（分数：0.50）A.B.C.D.(4).Which sentence below best expresses the essential information in the highlighted sentence in paragraph 3? Incorrect choices change the meaning in important ways or leave out essential information.AAlthough masonry walls could bear heavie: loads, architects preferre
18、d concrete walls because they were easier to build.BWalls used to be made of load-bearing masonry; now they were thin and made of concrete, so more windows were possible.CBecause tall buildings had such thin exterior walls, the windows needed curtain to prevent heat loss through the concrete.DMasonr
19、y replaced concrete as the material for outside walls, and this allowed skyscrapers to have a lot of windows.（分数：0.50）A.B.C.D.(5).According to the passage, which of the following statements is true of the earliest skyscrapers?AThey required the labor of stoneworkers.BThey were eight or more stories
20、high.CThey had very thick exterior walls.DThey were constructed with steel beams.（分数：0.50）A.B.C.D.(6).Why does the author discuss the elevator in paragraph 4?ATo illustrate an important use of cast iron technologyBTo compare the elevator with the office buildingCTo explain why early elevators were d
21、angerousDTo show how an innovation contributed to architecture（分数：0.50）A.B.C.D.(7).The word rentable in paragraph 4 is closest in meaning toAstrongBbeautifulClargeDdesirable（分数：0.50）A.B.C.D.(8).The word they in paragraph 5 refers toAinnovationsBusesCbuildingsDarchitects（分数：0.50）A.B.C.D.(9).The word
22、refined in paragraph 6 is closest in meaning toAreviewedBcopiedCmade cheaperDimproved（分数：0.50）A.B.C.D.(10).According to the passage, why did steel replace iron in the construction of skyscrapers?ASteel is stronger than iron and resists fatigue better.BSteel allows architects more freedom of expressi
23、on.CSteel is more available and less expensive than iron.DSteel does not rust, so it lasts longer than iron does.（分数：0.50）A.B.C.D.(11).It can be inferred from the passage that the author most likely believes which of the following about the skyscraper?AThe skyscraper is most beautiful when construct
24、ed of traditional materials.BCast iron technology and the elevator made the skyscraper possible.CMost technology used in the skyscraper existed before the nineteenth century.DThe definition of“true skyscraper“ will probably change in the future.（分数：0.50）A.B.C.D.(12).Look at the four squares, , , , a
25、nd , which indicate where the following sentence could be added to the passage. Where would the sentence best fit?Sophisticated plumbing was needed to service bathrooms and also to heat buildings with either steam or hot water.Skyscrapers differed from previous tall structures with their use of tech
26、nical innovations such as cast iron and the elevator. The development of cast iron technology, in which molten iron is poured into a mold, made modem plumbing possible. Cast iron pipes, fittings, and valves could deliver pressurized water to the many floors of tall buildings and drain wastewater out
27、. The invention of the mechanical elevator made it possible to construct even taller buildings. Before the elevator, office buildings were rarely more than four or five stories high. In 1857, the first passenger elevator equipped with safety brakes prevented the elevator from falling to the basement
28、 when a cable broke. The elevator made the upper floors as rentable as the first floor, liberating architecture from dependence on stairways and human muscle. . Square . Square . Square . Square . （分数：0.50）A.B.C.D.(13).Read the first sentence of a summary of the passage. Complete the summary by sele
29、cting the THREE answer 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 minor ideas in the passage. This question is worth 2 points.In the nineteenth century, there were s
30、everal important developments in the construction of tall buildings._Answer ChoicesHow to Score 2-Point QuestionsAnswers Correct Points Earned3 22 10-1 0AMasonry walls were built very thick at the base to support the buildings mass.BThe development of metal-frame construction eliminated the need for
31、 load-bearing walls.CHeating iron or subjecting it to pressure enabled ironworkers to create new shapes.DAn iron or steel skeleton supported the buildings weight, and concrete walls kept the weather out.EA growing need for office buildings and department stores led to the invention of the skyscraper
32、.FInventions such as the elevator and steel beams allowed taller buildings than ever before.（分数：0.50）填空项 1:_三、Set 2(总题数：1，分数：6.00)GENERAL SYSTEMS THEORY 1 The Greek word “systema“ means union, and scientists use the word “system“ to describe a collection of several components that are linked to one
33、another by functional relationships. Everything outside the system is known as the surroundings. Most scientific literature is a description of the components of a system, their relationships with one another, and their relationships with other systems. Although each science has its own systems with
34、 their own subject matter and networks of relationships, the formal characteristics of systems are similar for all sciences. The scientific discipline called general systems theory formulates principles that are valid for systems in general, no matter the elements involved and the relations or force
35、s among them. 2 Systems can be divided into two types: closed systems and open systems. A closed system receives no supply of energy from outside and transfers no energy outwards. An open system receives energy from its surroundings and transfers it out again. 3 A closed system is isolated fiom its
36、surroundings. The energy supply of a closed system is limited and is progressively used up by the processes operating within the system. The ability of the system to function decreases as the available energy is exhausted. Without any additional energy supplied from the outside, the systems processe
37、s stop altogether and no further change is possible in the system. A mill wheel supplied with water from a non-refillable container is a closed system. Once the container of water is empty, the wheel no longer turns because there is no water to turn it. In a truly closed system, the water would have
38、 to be collected below the mill wheel in a second container to ensure that the system did not supply any energy to the outside. 4 Some scientists argue that there are few truly closed systems in nature, and many define closed systems more broadly as those allowing energy but not mass to cross the sy
39、stem boundary. By this definition, the Earth system as a whole is a closed system. The boundary of the Earth system is the outer edge of the atmosphere, and except for the occasional meteorite, virtually no mass is exchanged between the Earth system and the rest of the universe. However, energy in t
40、he form of solar radiation passes from the sun, through the atmosphere to the Earths surface, which in turn radiates energy back out to space across the system boundary. Hence, energy passes across the Earths system boundary, but mass does not, making it a closed system. 5 In an open system, energy
41、and mass can be transferred between the system and its surroundings. Living organisms are open systems. They absorb light energy or chemical energy in the form of organic molecules and release heat and metabolic waste products, such as carbon dioxide, to the surroundings. Generally, relationships ex
42、ist between the components of a system and its surroundings, that is, other systems. Each open system is part of a larger system that receives and gives off energy. In an open system, the energy is continually resupplied from sources outside the system. In the example of the mill wheel, if the non-r
43、efillable water container is replaced by a reservoir fed continuously by a stream, it becomes an open system because the energy supply is renewed from the outside. 6 The natural environment is made up of open systems. These can behave as closed systems temporarily if the energy supply is halted for
44、a period. If, for example, the stream to the reservoir supplying the mill dries up for a long period, the energy consumption of the mill wheel cannot be balanced by new energy supply. The water in the reservoir is used up, and if the dry period is long enough, the mill wheel stops turning. Eventuall
45、y, the stream may flow again, filling the reservoir and turning the mill wheel again. This occurs because the stream-reservoir-mill system is itself a part of the Earths much larger systems of water circulation and water budget, which include condensation, precipitation, run-off, and evaporation. Th
46、e water systems receive their energy supply from the Earths heat budget, which in turn receives its energy supply from the suns radiation.（分数：6.00）(1).According to the passage, the concept of systems involves all of the following EXCEPTAthe components of a collectionBthe functional relationships amo
47、ng partsCthe links between different systemsDthe origin of the scientific method（分数：0.50）_(2).Which sentence below best expresses the essential information in the highlighted sentence in paragraph 1? Incorrect choices change the meaning in important ways or leave out essential information.AEvery sci
48、ence has a unique set of systems with characteristics and relationships that do not exist in any other science.BThe subject matter of systems is the same for all sciences, but the structure of system relationships can vary.CSystem components and relationships differ for each science, yet systems in
49、all sciences share similar properties.DIt is difficult to distinguish one system from another because all systems in all sciences have similar characteristics.（分数：0.50）A.B.C.D.(3).The word them in paragraph 1 refers toAsciencesBprinciplesCelementsDforces（分数：0.50）A.B.C.D.(4).The word exhausted in paragraph 3 is closest in meaning toAincreasedBusedCresuppliedDwasted（分数：0.50
