2000英语专四完形填空真题

2000英语专四完形填空真题Decidewhichofthechoicesgivenbelowwouldbestcompletethepassageifinsertedinthecorrespondingblanks.Markthebestchoiceforeachblankonyouranswersheet.

Thedifferencebetweenaliquidandagasisobvious(26)theconditionsoftemperatureandpressurecommonlyfoundatthesurfaceoftheEarth.Aliquidcanbekeptinanopencontainerand(27)ittothelevelofafreesurface.Agasformsnofreesurfacebut(28)todiffusethroughoutthespaceavailable;itmust(29)bekeptinaclosedcontainer,as(30)aplanet’satmosphere.Thedistinctionwasaprominentfeatureofearlytheories(31)thephasesofmatter.Inthenineteenthcentury,forexample,onetheorymaintainedthataliquidcouldbe“dissolved”inavaporwithoutlosingitsidentity,andanothertheoryheldthatthetwophasesare(32)differentkindsofmolecules(分子).Thetheoriesnowprevailing(33)aquitedifferentapproachbyemphasizingwhatliquidsandgaseshaveincommon.Theyarebothformsofmatterthathavenopermanentstructure,andtheybothfloweasily.Theyarefluids.

The(34)similarlyofliquidsandgasesbecomesclearlyapparentwhenthetemperatureandpressureareraisedsomewhat.(35)aclosedcontainerpartiallyfilledwithaliquidisheated.Theliquidexpandsor(36),becomeslessdense;someofitevaporates.(37),thevaporabovetheliquidsurfacebecomesdenserastheevaporatedmoleculesareaddedtoit.Thecombinationoftemperatureandpressure(38)thedensitiesbecomeequalis(39)thecriticalpoint.Abovethecriticalpointtheliquidandthegascannolongerbe(40);thereisasingle,undifferentiatedfluidphaseofuniformdensity.

26.A.inB.onC.underD.beyond

27.A.fillsB.befilledC.fillingD.tofill

28.A.intendsB.tendsC.inclinesD.contends

29.A.howeverB.neverthelessC.soD.therefore

30.A.intheeventofB.inthecaseofC.withaviewtoD.withreferenceto

31.A.havingdescribedB.describedC.describingD.tohavedescribed

32.A.madeupofB.consistedofC.constitutedofD.madefrom

33.A.applyB.adaptC.takeD.conduct

34.A.elementaryB.crucialC.rudimentaryD.fundamental

35.A.SupposeB.TosupposeC.BeingsupposedD.Supposed

36.A.inawordB.inthemeantimeC.inotherwordsD.inthatcase

37.A.SimilarlyB.IncontrastC.FurthermoreD.Instead

38.A.onthatB.onwhichC.at