专四阅读陆疏影.docx
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专四阅读陆疏影.docx
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专四阅读陆疏影
1
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.
1. Theauthorreferstotheimpactofrailroadsbeforethelate1860’sas“limited”because_B___.
A. thetrackdidnottakethedirectroutefromonecitytothenext
B.passengersandfreighthadtotransfertoothermodesoftransportationtoreachwesterndestinations
C.passengerspreferredstagecoaches
D.railroadtravelwasquiteexpensive
2. Whatcanbeinferredaboutcoachesandwagonfreightersastherailroadexpanded?
D
A. Theydevelopedcompetingroutes.
B.Theirdriversrefusedtoworkfortherailroads.
C.Theybegantospecializeinprivateinvestment.
D.Therewereinsufficientnumbersoftrainedpeopletooperatethem.
3. WhydoestheauthormentiontheSierraNevadainline17?
D
A. ToarguethatamoredirectroutetotheWestcouldhavebeentaken.
B.ToidentifyahistoricallysignificantmountainrangeintheWest.
C.Topointoutthelocationofaserioustrainaccident.
D.Togiveanexampleofanobstaclefacedbythecentralpacific.
4. Theword“subsidy”inline27isclosestinmeaningto _B____.
A.persuasion
B.financing
C.explanation
D.penalty
2
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,sothatthemarineorganismsthatprovidetheirfoodhaveachancetomultiply.Ifitwerenotforthisfaculty,theywoulddevourallthefoodavailableinashorttimeandwouldprobablystarvethemselvesoutofexistence.Butthemostspectacularthingabouttheseacucumberisthewayitdefendsitself.Itsmajorenemiesarefishandcrabs,whenattacked,itsquirtsallitsinternalorgansintowater.Italsocastsoffattachedstructuressuchastentacles.Theseacucumberwilleviscerateandregenerateitselfifitisattackedoreventouched;itwilldothesameifthesurroundingwatertemperatureistoohighorifthewaterbecomestoopolluted.
5. Accordingtothepassage,whyistheshapeofseacucumbersimportant?
B
A.Ithelpsthemtodigesttheirfood.
B.Ithelpsthemtoprotectthemselvesfromdanger.
C.Itmakesiteasierforthemtomovethroughthemud.
D.Itmakesthemattractivetofish.
6. Thefourthparagraphofthepassageprimarilydiscusses__C__.
A.thereproductionofseacucumbers
B.thefoodsourcesofseacucumbers
C.theeatinghabitsofseacucumbers
D.threatstoseacucumbers’existence
7. Whatcanbeinferredaboutthedefensemechanismsoftheseacucumber?
A
A.Theyareverysensitivetosurroundingstimuli.
B.Theyarealmostuseless.
C.Theyrequiregroupcooperation.
D.Theyaresimilartothoseofmostseacreatures.
8. WhichofthefollowingwouldNOTcauseaseacucumbertoreleaseits
internal organsintothewater?
B
A.Atouch.
B.Food.
C.Unusuallywarmwater.
D.Pollution.
3
Humanbeingshaveusedtoolsforaverylongtime.Insomepartsoftheworldyoucanstillfindtoolsthatpeopleusedmorethantwomillionyearsago.Theymadethesetoolsbyhittingonestoneagainstanother.Inthisway,theybrokeoffpiecesfromoneofthestones.Thesechipsofstonewereusuallysharpononeside.Peopleusedthemforcuttingmeatandskinfromdeadanimals,andformakingothertoolsoutofwood.Humanbeingsneededtousetoolsbecausetheydidnothavesharpteethlikeothermeat-eatinganimals,suchaslionsandtigers.Toolshelpedpeopletogetfoodmoreeasily.Workingwithtoolsalsohelpedtodevelophumanintelligence.Thehumanbraingrewbigger,andhumanbeingsbegantoinventmoreandmoretoolsandmachines.
Thestonechipwasoneofthefirsttoolsthatpeopleused,andperhapsitisthemostimportant.Somescientistssaythatitwasthekeytosuccessofmankind.Since1960anewkindoftoolhasappeared.Alittlechipthissiliconchip—ofsiliconcrystal.Itissmallerthanafingernail,butitcanstoremorethanamillion“bits”ofinformation.Itisanelectronicbrain.Everyyearthesechipsgetcleverer,buttheirsizegetssmaller,andtheircostgetsless.Theyareusedinwatches,calculatorsandintelligentmachinesthatwecanuseinmanyways.Inthefuture,wewillnotneedtoworkwithtoolsintheoldway.Machineswilldoeverythingforus.Theywilleventalkandplaygameswithus.Peoplewillhaveplentyofsparetime.Butwhatwilltheydowithit?
Humanbeingsusedstonechipsformorethantwomillionyears,buthumanlifechangedverylittleinthattime.Wehaveusedsiliconchipsforonlyafewyears,butlifeischangingfastereveryday.Whatwilllifebeliketwentyyearsfromnow?
Whatwilltheworldbeliketwomillionyearsfromnow?
9. Thestonechipisthoughttobethemostimportanttoolbecauseit__D____.
A.wasoneofthefirsttools
B.developedhumancapabilities
C.ledtotheinventionofmachines
D.wascrucialtothedevelopmentofmankind
10. Attheendofthepassagetheauthorseemstosuggestthatlifeinfutureis__B____.
A.disastrous
B.unpredictable
C.exciting
D.colorful
4.
Californiaisalandofvarietyandcontrast.Almosteverytypeofphysicallandfeature,sortofarcticicefieldsandtropicaljunglescanbefoundwithinitsborders.Sharplycontrastingtypesoflandoftenlieveryclosetooneanother.PeoplelivinginBakersfield,forinstance,canvisitthePacificOceanandthecoastalplain,thefertileSanJoaquinValley,thearidMojaveDesert,andthehighSierraNevada,allwithinaradiusofabout100miles.Inotherareas,itispossibletogosnowskiinginthemorningandsurfingintheeveningofthesameday,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.Someofitslakes,likeOwensLakeinDeathValley,arenotlakesatall:
theyaredried-uplakebeds.Inadditiontomountains,lakes,valleys,deserts,andplateaus,Cali
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