首页
外语
计算机
考研
公务员
职业资格
财经
工程
司法
医学
专升本
自考
实用职业技能
登录
外语
Although recent years have seen substantial reductions in noxious pollutants from individual motor vehicles, the number of such
Although recent years have seen substantial reductions in noxious pollutants from individual motor vehicles, the number of such
admin
2014-12-26
28
问题
Although recent years have seen substantial reductions in noxious pollutants from individual motor vehicles, the number of such vehicles has been steadily increasing. Consequently, more than 100 cities in the United States still have levels of carbon monoxide, particulate matter, and ozone(generated by photochemical reactions with hydrocarbons from vehicle exhaust)that exceed legally established limits. There is a growing realization that the only effective way to achieve further reductions in vehicle emissions—short of a massive shift away from the private automobile—is to replace conventional diesel fuel and gasoline with cleaner-burning fuels 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 than those of gasoline. These molecules burn more cleanly than gasoline, in part because they have fewer, if any, carbon-carbon bonds and the hydrocarbons they do emit are less likely to generate ozone. The combustion of larger molecules, which have multiple carbon-carbon bonds involves a more complex series of reactions. These reactions increase the probability of incomplete combustion and are more likely to release uncombusted and photochemically active hydrocarbon compounds into the atmosphere. On the other hand, alternative fuels do have drawbacks. Compressed natural gas would require that vehicles have set of heavy fuel tanks—a serious liability in terms of performance and fuel efficiency—and liquefied petroleum gas faces fundamental limits on supply.
Ethanol and methanol, on the other hand, have important advantages over other carbon-based alternative fuels: they have higher energy content per volume and would require minimal changes in the existing network for distributing motor fuel. Ethanol is commonly used as a gasoline supplement, but it is currently about twice as expensive as methanol, the low cost of which is one of its attractive features. Methanol’ s most attractive feature, however, is that it can reduce by about 90 percent the vehicle emissions that form ozone, the most serious urban air pollutant.
Like any alternative fuel, methanol has its critics. Yet much of the criticism is based on the use of "gasoline clone" vehicles that do not incorporate even the simplest design improvements that are made possibly with the use of methanol. It is true, for example, that a given volume of methanol provides only about one-half of the energy that gasoline and diesel fuel do; other things being equal, the fuel tank would have to be somewhat larger and heavier. However, since methanol-fuelled vehicles could be designed to be much more efficient than "gasoline clone" vehicles fuelled with methanol, they would need comparatively less fuel. Vehicles incorporating only the simplest of the engine improvements that methanol makes feasible would still contribute to an immediate lessening of urban air pollution.
It can be inferred that the author of the text most likely regards the criticism of methanol as______.
选项
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
答案
A
解析
细节题。根据criticism of methanol定位到最后一段Like any alternativefuel.methanol has its critics.Yet much of the criticism is based on the use of“gasolineclone”vehicles that do not incorporate even the simplest design improvements that aremade possibly with the use of methanol.“和其他的替代燃料一样,甲醇也遭到了非难。可大多数批评都建立在使用‘汽油系列’的车辆不进行最简单的设计改进以可能使用甲醇燃料的基础上。”批评的不足之处在于假设的基础,所以答案选A。
转载请注明原文地址:https://kaotiyun.com/show/2Km7777K
0
大学英语六级
相关试题推荐
A、Itmovesintoaslopingpositionandhasthepossibilityofcollapse.B、Itsbeautifulscenerywelcomes1billiontouristsonM
CanthePCIndustryResurrectItself?A)InternetDataCenter’s(IDC)recentreportstatedthatPCshipmentsdeclined13.9%lastqu
Go(围棋)isanancientAsiangame.Inrecentyears,computerexperts,particularlythose【C1】______inartificialintelligence,have
Go(围棋)isanancientAsiangame.Inrecentyears,computerexperts,particularlythose【C1】______inartificialintelligence,have
A、Accordingtothetimethephotosweretaken.B、Accordingtothesubjectsthephotosreflect.C、Accordingtotheculturalangle
A、Thecold,darklivingenvironment.B、Theincompressibilityofwater.C、Theremovalofthehabitat.D、Thehighdensityofwater
A、Warmerwatertemperature.B、Lessmarinelife.C、Ariseofsealevel.D、Colderwinds.C细节题。对话结尾处女士说,南极洲1/10的冰川融化将会导致全球海平面上升30英尺
A、TheliteraryworksofWinstonChurchill.B、ThespeechesWinstonChurchillgave.C、ThecontributionofWinstonChurchill.D、The
Whentelevisionisgood,nothing—notthetheater,notthemagazinesornewspapers—isbetter.Butwhentelevisionisbad,not
随机试题
企业职工一方与用人单位签订的有关女职工权益保护、工资调整机制的合同,属于专项集体合同。()
简述农村健康教育的主要内容。
下列可引起金属音调咳嗽的是
男,72岁。上下牙全部缺失,下颌弓明显宽于上颌弓,余未见异常对后牙数目的正确处理方法为
A.外痔B.内痔C.混合痔D.直肠脱垂E.环形痔排便时脱出肛门,需手推才能还纳的圆形肿物是
未成年人若要实行人工流产手术,有权签署手术同意书的人是
下列有关分部分项工程量清单编制的表述,正确的是()。
以下说法不正确的是()。
我国最早在现代意义上使用“课程”这一术语的教育家是_________。
A、Barbican.B、St.John’sWood.C、Morgan’sWalk.D、Battersea.AJamesMilligan介绍了四个目前最风靡的居住地,并提到喜欢夜晚安静的人们更倾向于选择Barbican。因此答案为A)。
最新回复
(
0
)