英语专业四级阅读理解练习三附答案解析.docx

英语专业四级阅读理解练习三附答案解析.docx

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英语专业四级阅读理解练习三附答案解析

PARTⅡ

SECTIONAREADINGCOMPREHENSION［25MIN.］

Inthissectiontherearefourpassagesfollowedbyfifteenquestionsorunfinishedstatements,eachwithfoursuggestedanswersmarkedA,B,CandD.Choosetheonethatyouthinkisthecorrectanswer.MarkyourchoiceonyourANSWERSHEET.

TEXTA

Beforethemid1860’s,theimpactoftherailroadsintheUnitedStateswaslimited,inthesensethatthetracksendedatthisMissouriRiver,approximatelythecenterofthecountry.Atthepointthetrainsturnedtheirfreight,mail,andpassengersovertosteamboats,wagons,andstagecoaches.Thismeantthatwagonfreighting,stagecoaching,andsteamboatingdidnotcometoanendwhenthefirsttrainappeared;rathertheybecamesupplementsorfeeders.Eachnew“endoftrack”becameacenterforanimaldrawnorwaterbornetransportation.Themajoreffectoftherailroadwastoshortenthedistancethathadtobecoveredbytheolder,slower,andmorecostlymeans.Wagonfreighterscontinuedoperatingthroughoutthe1870’sand1880’sandintothe1890’s.Althoughoverconstantlyshrinkingroutes,andcoachesandwagonscontinuedtocrisscrosstheWestwherevertherailshadnotyetbeenlaid.Thebeginningofamajorchangewasforeshadowedinthelater1860’s,whentheUnionPacificRailroadatlastbegantobuildwestwardfromtheCentralPlainscityofOmahatomeettheCentralPacificRailroadadvancingeastwardfromCaliforniathroughtheformidablebarrieroftheSierraNevada.AlthoughPresidentAbrahamLincolnsignedtheoriginalPacificRailroadbillin1862andarevised,financiallymuchmoregenerousversionin1864,littleconstructionwascompleteduntil1865ontheCentralPacificand1866ontheUnionPacific.TheprimaryreasonwasskepticismthataRailroadbuiltthroughsochallengingandthinlysettledastretchofdesert,mountain,andsemiaridplaincouldpayaprofit.Inthewordsofaneconomist,thiswasacaseof“prematureenterprise”,wherenotonlythecostofconstructionbutalsotheveryhighriskdeterredprivateinvestment.IndiscussingthePacificRailroadbill,thechairofthecongressionalcommitteebluntlystatedthatwithoutgovernmentsubsidynoonewouldundertakesounpromisingaventure;yetitwasanationalnecessitytolinkEastandWesttogether.

16.Theauthorreferstotheimpactofrailroadsbeforethelate1860’sas“limited”because____

A.thetrackdidnottakethedirectroutefromonecitytothenext

B.passengersandfreighthadtotransfertoothermodesoftransportationtoreachwesterndestinations

C.passengerspreferredstagecoaches

D.railroadtravelwasquiteexpensive

17.Whatcanbeinferredaboutcoachesandwagonfreightersastherailroadexpanded?

A.Theydevelopedcompetingroutes.

B.Theirdriversrefusedtoworkfortherailroads.

C.Theybegantospecializeinprivateinvestment.

D.Therewereinsufficientnumbersoftrainedpeopletooperatethem.

18.WhydoestheauthormentiontheSierraNevadainline17?

A.ToarguethatamoredirectroutetotheWestcouldhavebeentaken.

B.ToidentifyahistoricallysignificantmountainrangeintheWest.

C.Topointoutthelocationofaserioustrainaccident.

D.Togiveanexampleofanobstaclefacedbythecentralpacific.

19.Theword“subsidy”inline27isclosestinmeaningto_____.

A.persuasionB.financingC.explanationD.penalty

TEXTB

Certainlynocreatureintheseaisodderthanthecommonseacucumber.Alllivingcreature,especiallyhumanbeings,havetheirpeculiarities,buteverythingaboutthelittleseacucumberseemsunusual.Whatelsecanbesaidaboutabizarreanimalthat,amongothereccentricities,eatsmud,feedsalmostcontinuouslydayandnightbutcanlivewithouteatingforlongperiods,andcanbepoisonousbutisconsideredsupremelyediblebygourmets?

Forsomefiftymillionyears,despiteallitseccentricities,theseacucumberhassubsistedonitsdietofmud.Itisadaptableenoughtoliveattachedtorocksbyitstubefeet,underrocksinshallowwater,oronthesurfaceofmudflats.CommonincoolwateronbothAtlanticandPacificshores,ithastheabilitytosuckupmudorsandanddigestwhatevernutrientsarepresent.Seacucumberscomeinavarietyofcolors,rangingfromblacktoreddishbrowntosandcolorandnearlywhite.Oneformevenhasvividpurpletentacles.Usuallythecreaturesarecucumbershaped—hencetheirname—andbecausetheyaretypicallyrockinhabitants,thisshape,combinedwithflexibility,enablesthemtosqueezeintocreviceswheretheyaresafefrompredatorsandoceancurrents.

Althoughtheyhavevoraciousappetites,eatingdayandnight,seacucumbershavethecapacitytobecomequiescentandliveatalowmetabolicrate—feedingsparinglyornotatallforlongperiods,sothatthemarineorganismsthatprovidtheirfoodhaveachancetomultiply.Ifitwerenotforthisfaculty,theywoulddevourallthefoodavailableinashorttimeandwouldprobablystarvethemselvesoutofexistence.

Butthemostspectacularthingabouttheseacucumberisthewayitdefendsitself.Itsmajorenemiesarefishandcrabs,whenattacked,itsquirtsallitsinternalorgansintowater.Italsocastsoffattachedstructuressuchastentacles.Theseacucumberwilleviscerateandregenerateitselfifitisattackedoreventouched;itwilldothesameifthesurroundingwatertemperatureistoohighorifthewaterbecomestoopolluted.

20.Accordingtothepassage,whyistheshapeofseacucumbersimportant?

A.Ithelpsthemtodigesttheirfood.

B.Ithelpsthemtoprotectthemselvesfromdanger.

C.Itmakesiteasierforthemtomovethroughthemud.

D.Itmakesthemattractivetofish.

21.Thefourthparagraphofthepassageprimarilydiscusses____.

A.thereproductionofseacucumbers

B.thefoodsourcesofseacucumbers

C.theeatinghabitsofseacucumbers

D.threatstoseacucumbers’existence

22.Whatcanbeinferredaboutthedefencemechanismsoftheseacucumber?

A.Theyareverysensitivetosurroundingstimuli.

B.Theyarealmostuseless.

C.Theyrequiregroupcooperation.

D.Theyaresimilartothoseofmostseacreatures.

23.WhichofthefollowingwouldNOTcauseaseacucumbertoreleaseitsinternalorgansintothewater?

A.Atouch.B.Food.

C.Unusuallywarmwater.D.Pollution.

TEXTC

Humanbeingshaveusedtoolsforaverylongtime.Insomepartsoftheworldyoucanstillfindtoolsthatpeopleusedmorethantwomillionyearsago.Theymadethesetoolsbyhittingonestoneagainstanother.Inthisway,theybrokeoffpiecesfromoneofthestones.Thesechipsofstonewereusuallysharpononeside.Peopleusedthemforcuttingmeatandskinfromdeadanimals,andalsoformakingothertoolsoutofwood.Humanbeingsneededtousetoolsbecausetheydidnothavesharpteethlikeothermeateatinganimals,suchaslionsandtigers.Toolshelpedpeopletogetfoodmoreeasily.

Workingwithtoolsalsohelpedtodevelophumanintelligence.Thehumanbraingrewbigger,andhumanbeingsbegantoinventmoreandmoretoolsandmachines.Thestonechipwasoneofthefirsttoolsthatpeopleused,andperhapsitisthemostimportant.Somescientistssaythatitwasthekeytosuccessofmankind.

Since1960anewkindoftoolhasappeared.Thisisthesiliconchip—alittlechipofsiliconcrystal.Itissmallerthanafingernail,butitcanstoremorethanamillion“bits”ofinformation.Itisanelectronicyearthesechipsgetcleverer,buttheirsizegetssmaller,andtheircostgetsless.Theyareusedinwatches,calculatorsandintelligentmachinesthatwecanuseinmanyways.

Inthefuturewewillnotneedtoworkwithtoolsintheoldway.Machineswilldoeverythingforus.Theywilleventalkandplaygameswithus.Peoplewillhaveplentyofsparetime.Butwhatwilltheydowithit?

Humanbeingsusedstonechipsformorethantwomillionyears,buthumanlifechangedverylittleinthattime.Wehaveusedsiliconchipsforonlyafewyears,butlifeischangingfastereveryday.Whatwilllifebeliketwentyyearsfromnow?

Whatwilltheworldbeliketwomillionyearsfromnow?

24.Thestonechipisthoughttobethemostimportanttoolbecauseit______.

A.wasoneofthefirsttools

B.developedhumancapabilities

C.ledtotheinventionofmachines

D.wascrucialtothedevelopmentofmankind

25.Attheendofthepassagetheauthorseemstosuggestthatlifeinfutureis______.

A.disastrousB.unpredictable

C.excitingD.colorful

TEXTD

Californiaisalandofvarietyandcontrast.Almosteverytypeofphysicallandfeature,sortofarcticicefieldsandtropicaljunglescanbefoundwithinitsborders.Sharplycontrastingtypesoflandoftenlieveryclosetooneanother.

PeoplelivinginBakersfield,forinstance,canvisitthePacificOceanandthecoastalplain,thefertileSanJoaquinValley,thearidMojaveDesert,andthehighSierraNevada,allwithinaradiusofabout100miles.Inotherareasitispossibletogosnowskiinginthemorningandsurfingintheeveningofthesameday,withouthavingtotravellongdistance.

ContrastaboundsinCalifornia.ThehighestpointintheUnitedStates（outsideAlaska）isinCalifornia,andsoisthelowestpoint（includingAlaska）.MountWhitney,14,494feetabovesealevel,isseparatedfromDeathValley,282feetbelowsealevel,byadistanceofonly100miles.Thetwoareashaveadifferenceinaltitudeofalmostthreemiles.

Californiahasdeep,clearmountainlakeslikeLakeTahoe,thedeepestinthecountry,butitalsohasshallow,saltydesertlakes.IthasLakeTulainyo,12,020feetabovesealevel,andthelowestlakeinthecountry,theSaltonSea,236feetbelowsealevel.Someofits