1、托福（阅读）模拟试卷 9及答案与解析 一、 Sections Three： Reading Comprehension 0 “Weather and Chaotic Systems“ Weather and climate are closely related, but they are not quite the same thing. In any particular location, some days may be hotter or cooler, clearer or cloudier, calmer or stormier than others. The ever-var
2、ying combination of winds, clouds, temperature, and pressure is what we call weather. Climate is the long-term average of weather, which means it can change only on much longer time scales. The complexity of weather makes it difficult to predict, and at best, the local weather can be predicted only
3、a week or so in advance. Scientists today have a very good understanding of the physical laws and mathematical equations that govern the behavior and motion of atoms in the air, oceans, and land. Why, then, do we have so much trouble predicting the weather? To understand why the weather is so unpred
4、ictable we must look at the nature of scientific prediction. Suppose you want to predict the location of a car on a road 1 minute from now. You need two basic pieces of information: where the car is now, and how fast it is moving. If the car is now passing Smith Road and heading north at 1 mile per
5、minute, it will be 1 mile north of Smith Road in 1 minute. Now, suppose you want to predict the weather. Again, you need two basic types of information: (1) the current weather and (2) how weather changes from one moment to the next. You could attempt to predict the weather by creating a “model worl
6、d.“ For example, you could overlay a globe of the Earth with graph paper and then specify the current temperature, pressure, cloud cover, and wind within each square. These are your starting points, or initial conditions. Next, you could input all the initial conditions into a computer, along with a
7、 set of equations (physical laws) that describe the processes that can change weather from one moment to the next. Suppose the initial conditions represent the weather around the Earth at this very moment and you run your computer model to predict the weather for the next month in New York City. The
8、 model might tell you that tomorrow will be warm and sunny, with cooling during the next week and a major storm passing through a month from now. But suppose you run the model again, making one minor change in the initial conditions say, a small change in the wind speed somewhere over Brazil. A This
9、 slightly different initial condition will not change the weather prediction for tomorrow in New York City. B But for next months weather, the two predictions may not agree at all! C The disagreement between the two predictions arises because the laws governing weather can cause very tiny changes in
10、 initial conditions to be greatly magnified over time. D This extreme sensitivity to initial conditions is sometimes called the butterfly effect: If initial conditions change by as much as the flap of a butterflys wings, the resulting prediction may be very different. The butterfly effect is a hallm
11、ark of chaotic systems. Simple systems are described by linear equations in which, for example, increasing a cause produces a proportional increase in an effect. In contrast, chaotic systems are described by nonlinear equations, which allow for subtler and more intricate interactions. For example, t
12、he economy is nonlinear because a rise in interest rates does not automatically produce a corresponding change in consumer spending. Weather is nonlinear because a change in the wind speed in one location does not automatically produce a corresponding change in another location. Despite their name,
13、chaotic systems are not necessarily random. In fact, many chaotic systems have a kind of underlying order that explains the general features of their behavior even while details at any particular moment remain unpredictable. In a sense, many chaotic systems like the weather are “predictably unpredic
14、table.“ Our understanding of chaotic systems is increasing at a tremendous rate, but much remains to be learned about them. 1 According to the passage, it will be difficult to predict weather （ A） unless we learn more about chaotic systems （ B） because we dont communicate globally （ C） without more
15、powerful computers （ D） until we understand the physical laws of atoms 2 The word particular in the passage is closest in meaning to （ A） basic （ B） specific （ C） unusual （ D） new 3 The word govern in the passage is closest in meaning to （ A） change （ B） control （ C） show （ D） explain 4 Why does the
16、 author mention “a car“ in paragraph 3? （ A） The car is an example of how conditions are used to make predictions. （ B） The author digresses in order to tell a story about a car. （ C） The car introduces the concept of computer models. （ D） The mathematical equations for the car are very simple to un
17、derstand. 5 Why do the predictions disagree for the computer model described in paragraph 5? （ A） The conditions at the beginning were very different. （ B） The model was not accurately programmed. （ C） Computer models cannot predict weather. （ D） Over time models are less reliable. 6 Why is weather
18、considered a chaotic system? （ A） Because it is made up of random features （ B） Because it is not yet very well understood （ C） Because it is described by nonlinear equations （ D） Because it does not have an orderly structure 7 Based on information in paragraph 6, which of the following best explain
19、s the term “butterfly effect“? （ A） Slight variations in initial conditions can cause very different results. （ B） A butterflys wings can be used to predict different conditions in various locations. （ C） The weather is as difficult to predict as the rate of a butterflys wings when it flaps them. （
20、D） A butterfly flaps its wings in one location, which automatically produces a result In another place. 8 The phrase in which in the passage refers to （ A） the butterfly effect （ B） chaotic systems （ C） simple systems （ D） linear equations 9 Why does the author mention “the economy“ in paragraph 7?
21、（ A） To contrast a simple system with a chaotic system （ B） To provide an example of another chaotic system （ C） To compare nonlinear equations with linear equations （ D） To prove that all nonlinear systems are not chaotic 10 The word features in the passage is closest in meaning to （ A） problems （
22、B） exceptions （ C） characteristics （ D） benefits 11 In paragraph 8, the author suggests that our knowledge of chaotic systems （ A） will never allow us to make accurate predictions （ B） has not improved very much over the years （ C） reveals details that can be predicted quite accurately （ D） requires
23、 more research by the scientific community 12 Look at the four squares that show where the following sentence could be inserted in the passage. For next weeks weather, the new model may yield a slightly different prediction. Where could the sentence best be added? Click on a square to insert the sen
24、tence in the passage. 13 An introduction for a short summary of the passage appears below. Complete the summary by selecting the THREE answer choices that mention the most important points in the passage. Some sentences do not belong in the summary because they express ideas that are not included in
25、 the passage or are minor points from the passage. This question is worth 2 points. Because weather is a chaotic system, it is very difficult to predict. - - - Answer Choices A The accuracy of weather prediction will improve as we make progress in the application of computers to equations. B It is v
26、ery easy to make predictions about the location of a car when you know where it is and how fast it is going. C A slight variation in initial conditions will cause a very different prediction for weather over the long term. D Because weather is chaotic but not random, it may be described by nonlinear
27、 equations that provide for sensitive interactions. E The economic system demonstrates chaotic behavior, and it must be represented by a nonlinear equation. F Weather is predictable only within a time frame of a few weeks because of the nature of scientific prediction. 13 “Building with Arches“ Roun
28、d Arch and Vault Although the round arch was used by the ancient peoples of Mesopotamia several centuries before our common era, it was most fully developed by the Romans, who perfected the form in the 2nd century b.c.e. The arch has many virtues. In addition to being an attractive form, it enables
29、the architect to open up fairly large spaces in a wall without risking the buildings structural soundness. These spaces admit light, reduce the weight of the walls, and decrease the amount of material needed. As utilized by the Romans, the arch is a perfect semicircle, although it may seem elongated
30、 if it rests on columns. It is constructed from wedge-shaped pieces of stone that meet at an angle always perpendicular to the curve of the arch. Because of tensions and compressions inherent in the form, the arch is stable only when it is complete, when the topmost stone, the keystone, has been set
31、 in place. For this reason an arch under construction must be supported from below, usually by a wooden framework. Among the most elegant and enduring of Roman structures based on the arch is the Pont du Gard at Nimes, France, built about 15 c.e. when the empire was nearing its farthest expansion. A
32、t this time, Roman industry, commerce, and agriculture were at their peak. Engineering was applied to an ambitious system of public-works projects, not just in Italy but in the outlying areas as well. The Pont du Gard functioned as an aqueduct, a structure meant to transport water, and its lower lev
33、el served as a footbridge across the river. That it stands today virtually intact after nearly two thousand years (and is crossed by cyclists on the route of the famous Tour de France bicycle race) testifies to the Romans brilliant engineering skills. Visually, the Pont du Gard exemplifies the best
34、qualities of arch construction. Solid and heavy, obviously durable, it is shot through with open spaces that make it seem light and its weight-bearing capabilities effortless. When the arch is extended in depth when it is, in reality, many arches placed flush one behind the other the result is calle
35、d a barrel vault. This vault construction makes it possible to create large interior spaces. The Romans made great use of the barrel vault, but for its finest expression we look many hundreds of years later, to the churches of the Middle Ages. The church of Sainte-Foy, in the French city of Conques,
36、 is an example of the style prevalent throughout Western Europe from about 1050 to 1200 a style known as Romanesque. Earlier churches had used the Roman round arch and barrel vault so as to add height to their churches. Until this period most churches had beamed wooden roofs, which not only posed a
37、threat of fire but also limited the height to which architects could aspire. With the stone barrel vault, they could achieve the soaring, majestic space we see in the nave of Sainte-Foy to span the spaces between the interior columns that ultimately held up the roof. With the Romanesque style, build
38、ers set a stone barrel vault as a ceiling over the nave, hiding the roof structure from view. The barrel vault unified the interior visually, providing a soaring, majestic climax to the rhythms announced by the arches below. Pointed Arch and Vault While the round arch and vault of the Romanesque era
39、 solved many problems and made many things possible, they nevertheless had certain drawbacks. For one thing, a round arch, to be stable, must be a semicircle; therefore, the height of the arch is limited by its width. Two other difficulties were weight and darkness. Barrel vaults are both literally
40、and visually heavy, calling for huge masses of stone to maintain their structural stability. They exert an outward thrust all along their base, which builders countered by setting them in massive walls that they dared not weaken with light-admitting openings. The Gothic period in Europe, which follo
41、wed the Romanesque, solved these problems with the pointed arch. A The pointed arch, while seemingly not very different from the round one, offers many advantages. IS Because the sides arc up to a point, weight is channeled down to the ground at a steeper angle, and therefore the arch can be taller.
42、 The vault constructed from such an arch also can be much taller than a barrel vault. C Architects of the Gothic period found they did not need heavy masses of material throughout the curve of the vault, as long as the major points of intersection were reinforced. D Glossary nave: the long central a
43、rea in a church with aisles on each side 14 Why does the author mention the “keystone“ in paragraph 1 ? （ A） To explain the engineering of an arch （ B） To provide historical background on arches （ C） To point out one of the virtues of arches （ D） To suggest an alternative to the arch 15 The word inh
44、erent in the passage is closest in meaning to （ A） uncertain （ B） unsatisfactory （ C） expansive （ D） essential 16 The Pont du Gard mentioned in paragraph 2 has all of the following characteristics EXCEPT （ A） It was an aqueduct. （ B） It is still being used. （ C） It was built 2000 years ago. （ D） It
45、was repaired recently. 17 The word virtually in the passage is closest in meaning to （ A） obviously （ B） accurately （ C） routinely （ D） practically 18 According to paragraph 3, what is the advantage of a barrel vault? （ A） It was used in the Middle Ages. （ B） Many arches were joined. （ C） The space
46、inside was larger. （ D） It was a typical Roman look. 19 What can be inferred from paragraph 4 about Romanesque architecture? （ A） Arches and barrel vaults were used in the designs. （ B） Wood beams characterized the buildings. （ C） The structures were smaller than those of Roman style. （ D） The archi
47、tecture was popular during the Roman occupation. 20 Which of the sentences below best expresses the information in the highlighted statement in the passage? The other choices change the meaning or leave out important information. （ A） Architects wanted to build higher ceilings in churches, but they
48、were limited because of the fire hazard caused by wooden beams in the roofs. （ B） The majority of the churches prior to this time were constructed with wooden roofs that caused a considerable fire hazard because of their height. （ C） The wood beams in the roofs of most churches before this period we
49、re a concern because of fire and the constraints they imposed on the height of the ceiling. （ D） The limitations on the architecture of the churches were a result of the construction materials and the limited vision of the architects. 21 The word achieve in the passage is closest in meaning to （ A） retain （ B） accomplish （ C） decorate （ D） finance 22 The word their in the passage refers to （ A） masses （ B） builders （ C） stone （ D） vaults 23 According to paragraph 5, why are Romanesque churches so dark? （ A） It was a characteristic of construction with pointed arches.
