GRE考试《阅读理解》练习题及答案8.docx
《GRE考试《阅读理解》练习题及答案8.docx》由会员分享，可在线阅读，更多相关《GRE考试《阅读理解》练习题及答案8.docx（10页珍藏版）》请在冰点文库上搜索。
GRE考试《阅读理解》练习题及答案8
GRE考试《阅读理解》练习题及答案（8）
GRE阅读题目解析:
机动车尾气排放导致空气污染
Although,recentyearshaveseensubstantialreductionsinnoxiouspollutantsfromindividualmotorvehicles,thenumberofsuchvehicleshasbeensteadilyincreasing,consequently,morethan100citiesintheUnitedStatesstillhavelevelsofcarbonmonoxide,particulatematter,andozone（generatedbyphotochemicalreactionswithhydrocarbonsfromvehicleexhaust）thatexceedlegallyestablishedlimits.Thereisagrowingrealizationthattheonlyeffectivewaytoachievefurtherreductionsinvehicleemissions—shortofamassiveshiftawayfromtheprivateautomobile—istoreplaceconventionaldieselfuelandgasolinewithcleaner-burningfuelssuchascompressednaturalgas,liquefiedpetroleumgas,ethanol,ormethanol.
Allofthesealternativesarecarbon-basedfuelswhosemoleculesaresmallerandsimplerthanthoseofgasoline.Thesemoleculesburnmorecleanlythangasoline,inpartbecausetheyhavefewer,ifany,carbon-carbonbonds,andthehydrocarbonstheydoemitarelesslikelytogenerateozone.Thecombustionoflargermolecules,whichhavemultiplecarbon-carbonbonds,involvesamorecomplexseriesofreactions.Thesereactionsincreasetheprobabilityofincompletecombustionandaremorelikelytoreleaseuncombustedandphotochemicallyactivehydrocarboncompoundsintotheatmosphere.Ontheotherhand,alternativefuelsdohavedrawbacks.Compressednaturalgaswouldrequirethatvehicleshaveasetofheavyfueltanks—aseriousliabilityintermsofperformanceandfuelefficiency—andliquefiedpetroleumgasfacesfundamentallimitsonsupply.
Ethanolandmethanol,ontheotherhand,haveimportantadvantagesoverothercarbonbasedalternativefuels:
theyhaveahigherenergycontentpervolumeandwouldrequireminimalchangesintheexistingnetworkfordistributingmotorfuel.Ethanoliscommonlyusedasagasolinesupplement,butitiscurrentlyabouttwiceasexpensiveasmethanol,thelowcostofwhichisoneofitsattractivefeatures.Methanol’smostattractivefeature,however,isthatitcanreducebyabout90percentthevehicleemissionsthatformozone,themostseriousurbanairpollutant.
Likeanyalternativefuel,methanolhasitscritics.Yetmuchofthecriticismisbasedontheuseof“gasolineclone”vehiclesthatdonotincorporateeventhesimplestdesignimprovementsthataremadepossiblewiththeuseofmethanol.Itistrue,forexample,thatagivenvolumeofmethanolprovidesonlyaboutone-halfoftheenergythatgasolineanddieselfueldo;otherthingsbeingequal,thefueltankwouldhavetobesomewhatlargerandheavier.However,sincemethanol-fueledvehiclescouldbedesignedtobemuchmoreefficientthan“gasolineclone”vehiclesfueledwithmethanol,theywouldneedcomparativelylessfuel.Vehiclesincorporatingonlythesimplestoftheengineimprovementsthatmethanolmakesfeasiblewouldstillcontributetoanimmediatelesseningofurbanairpollution.
1.Accordingtothepassage,incompletecombustionismorelikelytooccurwithgasolinethanwithanalternativefuelbecause
A.thecombustionofgasolinereleasesphotochemicallyactivehydrocarbons
B.thecombustionofgasolineinvolvesanintricateseriesofreactions
C.gasolinemoleculeshaveasimplemolecularstructure
D.gasolineiscomposedofsmallmolecules.
E.gasolineisacarbon-basedfuel
2.Whichofthefollowingmostcloselyparallelsthesituationdescribedinthefirstsentenceofthepassage?
A.Althoughatownreducesitspublicservicesinordertoavoidataxincrease,thetown’staxrateexceedsthatofothertownsinthesurroundingarea.
B.Althoughastatepassesstrictlawstolimitthetypeoftoxicmaterialthatcanbedisposedofinpubliclandfills,illegaldumpingcontinuestoincrease.
C.Althoughatown’scitizensreducetheirindividualuseofwater,thetown’swatersuppliescontinuetodwindlebecauseofasteadyincreaseinthetotalpopulationofthetown.
D.Althoughacountryattemptstoincreasethesaleofdomesticgoodsbyaddingataxtothepriceofimportedgoods,thesaleofimportedgoodswithinthecountrycontinuestoincrease.
E.Althoughacountryreducesthespeedlimitonitsnationalhighways,thenumberoffatalitiescausedbyautomobileaccidentscontinuestoincrease.
3.Itcanbeinferredfromthepassagethatavehiclespecificallydesignedtousemethanolforfuelwould
A.besomewhatlighterintotalbodyweightthanaconventionalvehiclefueledwithgasoline
B.bemoreexpensivetooperatethanaconventionalvehiclefueledwithgasoline
C.havealargerandmorepowerfulenginethanaconventionalvehiclefueledwithgasoline
D.havealargerandheavierfueltankthana“gasolineclone”vehiclefueledwithmethanol
E.averagemoremilespergallonthana“gasolineclone”vehiclefueledwithmethanol
4.Thepassagesuggestswhichofthefollowingaboutairpollution?
A.Furtherattemptstoreduceemissionsfromgasoline-fueledvehicleswillnothelplowerurbanair-pollutionlevels.
B.Attemptstoreducethepollutantsthatanindividualgasoline-fueledvehicleemitshavebeenlargelyunsuccessful.
C.Fewseriousattemptshavebeenmadetoreducetheamountofpollutantsemittedbygasoline-fueledvehicles.
D.Pollutantsemittedbygasoline-fueledvehiclesarenotthemostcriticalsourceofurbanairpollution.
E.Reductionsinpollutantsemittedbyindividualvehicleshavebeenoffsetbyincreasesinpollutionfromsourcesotherthangasoline-fueledvehicles.
1
Although,recentyearshaveseensubstantialreductionsinnoxiouspollutantsfromindividualmotorvehicles,thenumberofsuchvehicleshasbeensteadilyincreasing,consequently,morethan100citiesintheUnitedStatesstillhavelevelsofcarbonmonoxide,particulatematter,andozone（generatedbyphotochemicalreactionswithhydrocarbonsfromvehicleexhaust）thatexceedlegallyestablishedlimits.
尽管近年来单体机动车的有害排放物显著降低，但机动车总数一直稳步增加，结果是，美国超过100座城市的一氧化碳，有害悬浮颗粒，臭氧（机动车尾气与碳氢化合物发生光化学反应的产物）水平超过法定标准。
2
Thereisagrowingrealizationthattheonlyeffectivewaytoachievefurtherreductionsinvehicleemissions—shortofamassiveshiftawayfromtheprivateautomobile—istoreplaceconventionaldieselfuelandgasolinewithcleaner-burningfuelssuchascompressednaturalgas,liquefiedpetroleumgas,ethanol,ormethanol.
越来越多人相信唯一有效的减排方案——除了私家车大规模减少——就是用更清洁的燃料替换传统柴油和汽油，比如压缩天然气，液化石油气，乙醇，或甲醇。
（shortof此处为介词，除了，除非，otherthan）
3
Allofthesealternativesarecarbon-basedfuelswhosemoleculesaresmallerandsimplerthanthoseofgasoline.
这些替代燃料与汽油同属碳基燃料，但分子更小更简单。
4
Thesemoleculesburnmorecleanlythangasoline,inpartbecausetheyhavefewer,ifany,carbon-carbonbonds,andthehydrocarbonstheydoemitarelesslikelytogenerateozone.
这些分子比汽油燃烧更干净，某种程度上是因为它们含有更少的，如果有的话，碳碳键，且它们释放的碳氢化合物更不易产生臭氧。
5
Thecombustionoflargermolecules,whichhavemultiplecarbon-carbonbonds,involvesamorecomplexseriesofreactions.
大分子的氧化，会产生复合碳碳键，涉及更复杂的反应。
（不懂化学，翻错的话，请擅长化学的同学留言指导）
6
Thesereactionsincreasetheprobabilityofincompletecombustionandaremorelikelytoreleaseuncombustedandphotochemicallyactivehydrocarboncompoundsintotheatmosphere.
这些反应增加了不充分燃烧的可能性，也更可能向大气中释放未氧化且具有光化学反应活性的碳氢化合物。
7
Ontheotherhand,alternativefuelsdohavedrawbacks.
另一方面，替代燃料也有劣势。
8
Compressednaturalgaswouldrequirethatvehicleshaveasetofheavyfueltanks—aseriousliabilityintermsofperformanceandfuelefficiency—andliquefiedpetroleumgasfacesfundamentallimitsonsupply.
压缩天然气需要车辆加装一组沉重的油箱——难以实施也影响效率——而液化石油气面临严重的供给限制。
9
Ethanolandmethanol,ontheotherhand,haveimportantadvantagesoverothercarbonbasedalternativefuels:
theyhaveahigherenergycontentpervolumeandwouldrequireminimalchangesintheexistingnetworkfordistributingmotorfuel.
乙醇和甲醇，另一方面，相对于其他碳基替代燃料有重要优势：
单位体积所产生的能量更高，且对现有配给网络秩序做出最小改动。
10
Ethanoliscommonlyusedasagasolinesupplement,butitiscurrentlyabouttwiceasexpensiveasmethanol,thelowcostofwhichisoneofitsattractivefeatures.
乙醇通常被用作一种汽油的补充，但当前价格大概是甲醇的两倍，价格低是甲醇的一大优势。
11
Methanol’smostattractivefeature,however,isthatitcanreducebyabout90percentthevehicleemissionsthatformozone,themostseriousurbanairpollutant.
然而甲醇的最大优势，是能够减少机动车90%生成臭氧的排放，臭氧是最严重的城市空气污染物。
12
Likeanyalternativefuel,methanolhasitscritics.
和任何一种替代燃料一样，甲醇也受到批评。
13
Yetmuchofthecriticismisbasedontheuseof“gasolineclone”vehiclesthatdonotincorporateeventhesimplestdesignimprovementsthataremadepossiblewiththeuseofmethanol.
而批评大多基于市面上的车都是烧汽油的，没有针对可能转而使用甲醇做出任何设计上的改进。
（yet当yet引导让步关系时，可以替换为nevertheless，引导被强调的内容（与之相对地，although引导被让步的内容）。
gasolineclone不知道怎么翻译，意会吧。
Xclone指一系列有某种共同特点的事物。
）
14
Itistrue,forexample,thatagivenvolumeofmethanolprovidesonlyaboutone-halfoftheenergythatgasolineanddieselfueldo;otherthingsbeingequal,thefueltankwouldhavetobesomewhatlargerandheavier.
的确，比如说，甲醇只能提供相同体积的汽油或柴油燃料一半的能量;其他条件相同，（烧甲醇燃料的汽车）油箱会变得更大也更重。
15
However,sincemethanol-fueledvehiclescouldbedesignedtobemuchmoreefficientthan“gasolineclone”vehiclesfueledwithmethanol,theywouldneedcomparativelylessfuel.
然而，因为烧甲醇燃料的车可以被设计得比烧汽油的车烧甲醇更有效率，所以它们相对省油。
16
Vehiclesincorporatingonlythesimplestoftheengineimprovementsthatmakesmethanolfeasiblewouldstillcontributetoanimmediatelesseningofurbanairpollution.
对发动机做出最简单的改进，使车可以烧甲醇，仍可以帮助减少城市空气污染。
（原thatmethanolmakesfeasible改为thatmakesmethanolfeasible）
1.Accordingtothepassage,incompletecombustionismorelikelytooccurwithgasolinethanwithanalternativef
升级会员 