GRE阅读模拟在线练习附答案二百六十九

　　对于GRE阅读部分，最好的练习资料就是模拟资料。通过模拟练习，可以让大家更好地发现自己在备考中的不足，重点攻克自己的短板内容，有效的提升阅读分数。下面新东方在线GRE频道为大家整理了详细的内容，供大家参考。

点击查看》》》【GRE阅读真题在线练习附答案汇总】

　　Although, recent years have seen substantialreductions in noxious pollutants from individualmotor vehicles, the number of such vehicles hasbeen steadily increasing conse-quently, more than100 cities in the United States still have levels ofcarbon monoxide, particulate matter, and ozone(generated by photochemical, reactions withhydrocarbons from vehicle exhaust) that exceedlegally established limits. There is a growing, realization that the only effective way toachieve, further reductions in vehicle emissions-short of a massive shift away from theprivate automobile-is to replace conventional diesel fuel and gasoline with cleaner burningfuels such as compressed natural gas,liquefied petroleum gas, ethanol, or methanol.

　　All of these alternatives are carbon- based fuels whose molecules are smaller and simpler thanthose of gasoline. These molecules burn more cleanly than gasoline, in part because theyhave fewer, if and, carbon-carbon bonds, and the hydrocarbons they do emit are less likely togenerate ozone. The combustion of larger molecules, which have multiple carbon-carbonbonds, involves a more complex series of reactions. These reactions increase the probabilityof incomplete com-bustion and are more likely to release uncombusted and photochemicallyactive hydrocarbon compounds into the atmos-phere. On the other hand, alternative fuels dohave drawbacks. Compressed natural gas would require that vehicles have a set of heavy fueltanks-a serious liability in terms of perfor-mance and fuel efficiency and liquefied petroleumgas faces fundamental limits on supply.

　　Ethanol and methanol, on the other hand, have important advantages over other carbon-basedalternative fuels; they have a higher energy content per volume and would require minimalchanges in the existing network for distributing motor fuel. Ethanol is commonly used as agasoline supplement, but it is currently about twice as expensive as methanol, the low costof which is one of its attractive features. Methanol's most attractive feature, however, is thatit can reduce by about 90 percent the vehicle emissions that form ozone, the most seriousurban air pollutant.

　　Like any alternative fuel, methanol has its critics, Yet much of the criticism is based on the useof "gasoline clone" vehicles that do not incorporate even the simplest design improvementsthat are made possible with the use of methanol. It is true, for example, that a given volume ofmethanol provides only about one-half of the energy that gasoline and diesel fuel do; otherthings being equal, the fuel tank would have to be somewhat larger and heavier. However, since methanol-fueled vehicles could be designed to be much more efficient than "gasolineclone" vehicles fueled with methanol, they would need comparatively less fuel. Vehiclesincorporating only the simplest of the engine improvements that methanol makes feasiblewould still contribute to an immediate lessening of urban air pollution.

　　The author of the passage is primarily concerned with

　　A.countering a flawed argument that dismisses a possible solution to a problem

　　B.reconciling contradictory points of view about the nature of a problem

　　C.identifying the strengths of possible solutions to a problem

　　D.discussing a problem and arguing in favor of one solution to it

　　E.outlining a plan of action to solve a problem and discussing the obstacles blocking that plan

　　According to the passage, incomplete combustion is more likely to occur with gasolinethan with an alternative fuel because

　　A.the combustion of gasoline releases photochemically active hydrocarbons

　　B.the combustion of gasoline involves an intricate series of reactions

　　C.gasoline molecules have a simple molecular structure

　　D.gasoline is composed of small molecules.

　　E.gasoline is a carbon-based fuel

　　The passage suggests which of the following about air pollution?

　　A.Further attempts to reduce emissions from gasoline-fueled vehicles will not help lowerurban air-pollution levels.

　　B.Attempts to reduce the pollutants that an individual gasoline-fueled vehicle emits havebeen largely unsuccessful.

　　C.Few serious attempts have been made to reduce the amount of pollutants emitted bygasoline-fueled vehicles.

　　D.Pollutants emitted by gasoline-fueled vehicles are not the most critical source of urban airpollution.

　　E.Reductions in pollutants emitted by individual vehicles have been offset by increases inpollution from sources other than gasoline-fueled vehicles.

　　Which of the following most closely parallels the situation described in the firstsentence of the passage?

　　A.Although a town reduces its public services in order to avoid a tax increase, the town’s taxrate exceeds that of other towns in the surrounding area.

　　B.Although a state passes strict laws to limit the type of toxic material that can be disposedof in public landfills, illegal dumping continues to increase.

　　C.Although a town’s citizens reduce their individual use of water, the town’s water suppliescontinue to dwindle because of a steady increase in the total population of the town.

　　D.Although a country attempts to increase the sale of domestic goods by adding a tax to theprice of imported goods, the sale of imported goods within the country continues to increase.

　　E.Although a country reduces the speed limit on its national highways, the number of fatalitiescaused by automobile accidents continues to increase.

　　The author describes which of the following as the most appealing feature ofmethanol?

　　A.It is substantially less expensive than ethanol.

　　B.It could be provided to consumers through the existing motor fuel distribution system.

　　C.It has a higher energy content than other alternative fuels.

　　D.Its use would make design improvements in individual vehicles feasible.

　　E.Its use would substantially reduce ozone levels.

　　It can be inferred from the passage that a vehicle specifically designed to usemethanol for fuel would

　　A.be somewhat lighter in total body weight than a conventional vehicle fueled with gasoline

　　B.be more expensive to operate than a conventional vehicle fueled with gasoline

　　C.have a larger and more powerful engine than a conventional vehicle fueled with gasoline

　　D.have a larger and heavier fuel tank than a “gasoline clone” vehicle fueled with methanol

　　E.average more miles per gallon than a “gasoline clone” vehicle fueled with methanol

　　It can be inferred that the author of the passage most likely regards the criticism ofmethanol in the last paragraph as

　　A.flawed because of the assumptions on which it is based

　　B.inapplicable because of an inconsistency in the critics'arguments

　　C.misguided because of its exclusively technological focus

　　D.inaccurate because it ignores consumers'concerns

　　E.invalid because it reflects the personal bias of the critics

　　正确答案:D B A C E E A

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