GreatasNewtonwas,manyofhisideas____todayandarebeingmodifiedbytheworkofscientistsofourtime.

AsGilbertWhite，Darwin，andothersobservedlongago，allspeciesappeartohavetheinnatecapacitytoincreasetheirnumbersfromgenerationtogeneration.Thetaskforecologistsistountangletheenvironmentaandbiologicalfactorsthatholdthisintrinsiccapacityforpopulationgrowthincheckoverthelongrun.Thegreatvarietyofdynamicbehaviorsexhibitedbydifferentpopulationmakesthistaskmoredifficult：sompopulationsremainroughlyconstantfromyeartoyear;othersexhibitregularcyclesofabundanceandscarcity;stillothersvarywildly，withoutbreaksandcrashesthatareinsomecasesplainlycorrelatedwiththeweather，andinothercasesnot.Toimposesomeorderonthiskaleidoscopeofpatterns，oneschoolofthoughtproposesdividingpopulationsintotwogroups.Theseecologistspositthattherelativelysteadypopulationshavedensity-dependentgrowthparameters;thatis，ratesofbirth，death，andmigrationwhichdependstronglyonpopulationdensity.Thehighlyvaryingpopulationshavedensity-independentgrowthparameters，withvitalratesbuffetedbyenvironmentalevents;theseratesfluctuateinawaythatiswhollyindependentofpopulationdensity.Thisdichotomyhasitsuses，butitcancauseproblemsiftakentooliterally.Foronething，nopopulationcanbedrivenentirelybydensity-independentfactorsallthetime.Nomatterhowseverelyorunpredictablybirth，death，andmigrationratesmaybefluctuatingaroundtheirlong-termaverages，iftherewerenodensity-dependenteffects，thepopulationwould，inthelongrun，eitherincreaseordecreasewithoutbound(barringamiraclebywhichgainsandlossescanceledexactly)。Putanotherway，itmaybethatonaverage99percentofalldeathsinapopulationarisefromdensity-independentcauses，andonlyonepercentfromfactorsvaryingwithdensity.Thefactorsmakinguptheonepercentmayseemunimportant，andtheircausemaybecorrespondinglyhardtodetermine.Yet，whetherrecognizedornot，theywillusuallydeterminethelong-termaveragepopulationdensity.Inordertounderstandthenatureoftheecologist’sinvestigation，wemaythinkofthedensity-dependenteffectsongrowthparametersasthesignalecologistsaretryingtoisolateandinterpret，onethattendstomakethepopulationincreasefromrelativelylowvaluesordecreasefromrelativelyhighones，whilethedensity-independenteffectsacttoproducenoiseinthepopulationdynamics.Forpopulationsthatremainrelativelyconstant，orthatoscillatearoundrepeatedcycles，thesignalcanbefairlyeasilycharacterizedanditseffectsdescribed，eventhoughthecausativebiologicalmechanismmayremainunknown.Forirregularlyfluctuatingpopulations，wearelikelytohavetoofewobservationstohaveanyhopeofextractingthesignalfromtheoverwhelmingnoise.Butitnowseemsclearthatallpopulationsareregulatedbyamixtureofdensity-dependentanddensity-independenteffectsinvaryingproportions.

1.Theauthorofthetextisprimarilyconcernedwith

[A]Discussingtwocategoriesoffactorsthatcontrolpopulationgrowthandassessingtheirrelativeimportance.

[B]Describinghowgrowthratesinnaturalpopulationsfluctuateovertimeandexplainingwhythesechangesoccur.

[C]Proposingahypothesisconcerningpopulationsizeandsuggestingwaystotestit.

[D]Posingafundamentalquestionaboutenvironmentalfactorsinpopulationgrowthandpresentingsomecurrentlyacceptedanswer.

2.Itcanbeinferredfromthetextthattheauthorconsidersthedichotomydiscussedtobe

[A]Applicableonlytoerraticallyfluctuatingpopulations.

[B]instrumental，butonlyifitslimitationsarerecognized.

[C]Dangerouslymisleadinginmostcircumstances.

[D]Acompleteandsufficientwaytoaccountforobservedphenomena.

3.tothetext，allofthefollowingbehaviorshavebeenexhibitedbydifferentpopulationsEXCEPT

[A]Roughlyconstantpopulationlevelsfromyeartoyear.

[B]Regularcyclesofincreasesanddecreasesinnumbers.

[C]Erraticincreasesinnumberscorrelatedwiththeweather.

[D]Uncheckedincreasesinnumbersovermanygenerations.

4.Thediscussionconcerningpopulationinthethirdparagraphservesprimarilyto

[A]Demonstratethedifficultiesecologistsfaceinstudyingdensity-dependentfactorslimitingpopulationgrowth.

[B]Advocatemorerigorousstudyofdensity-dependentfactorsinpopulationgrowth.

[C]Provethatthedeathratesofanypopulationareneverentirelydensity-independent.

[D]underlinetheimportanceofevensmalldensity-dependentfactorsinregulatinglong-termpopulationdensities.

5.Inthetext，theauthordoesallofthefollowingEXCEPT

[A]Citetheviewsofotherbiologists.

[B]Defineabasicproblemthatthetextaddresses.

[C]Presentconceptualcategoriesusedbyotherbiologists.

[D]Describetheresultsofaparticularstudy.

Youmustpayimport____oncertaingoodsbroughtintothiscountry.

Thetimehascome_____wemakeextensiveuseofnuclearenergy.

Passage2

Questions6to10arebasedonthefollowingpassage:

Thehumanbraincontains10thousandmillioncellsandeachofthesemayhaveathousandconnections.(77)Suchenormousnumbersusedtodiscourageusandcauseustodismissthepossibilityofmakingamachinewithhuman-likeability,butnowthatwehavegrownusedtomovingforwardatsuchapacewecanbelesssure.Quitesoon,inonly10or20yearsperhaps,wewillbeabletoassembleamachineascomplexasthehumanbrain,andifwecanwewill.Itmaythentakeusalongtimetorenderitintelligentbyloadingintherightsoftware(软件)orbyalteringthearchitecturebutthattoowillhappen.

(78)Ithinkitcertainthatindecades,notcenturies,machinesofsilicon(硅)willarisefirsttorivalandthenexceedtheirhumanancestors.Oncetheyexceedustheywillbecapableoftheirowndesign.Inarealsensetheywillbeabletoreproducethemselves.Siliconwillhaveendedcarbon’slongcontrol.Andwewillnolongerbeabletoclaimourselvestobethefinestintelligenceintheknownuniverse.

Astheintelligenceofrobotsincreasestomatchthatofhumansandastheircostdeclinesthrougheconomiesofscalewemayusethemtoexpandourfrontiers,firstonearththroughtheirabilitytowithstandenvironments,harmfultoourselves.Thus,desertsmaybloomandtheoceanbedsbemined.Furtherahead,byacombinationofthegreatwealththisnewagewillbringandthetechnologyitwillprovide,theconstructionofavast,man-createdworldinspace,hometothousandsormillionsofpeople,willbewithinourpower.

6.Inwhatwaycanwemakeamachineintelligent?

A)Bymakingitworkinsuchenvironmentsasdeserts,oceansorspace.

B)Byworkinghardfor10or20years.

C)Byeitherproperlyprogrammingitorchangingitsstructure.

D)Byreproducingit.(C)

7.Whatdoesthewriterthinkaboutmachineswithhuman-likeability?

A)Hebelievestheywillbeusefultohumanbeings.

B)Hebelievesthattheywillcontrolusinthefuture.

C)Heisnotquitesureinwhatwaytheymayinfluenceus.

D)Hedoesn’tconsidertheconstructionofsuchmachinespossible.

8.Theword“carbon”(Line4,Para.2)standsfor________.

A)intelligentrobotsB)achemicalelementC)anorganicsubstanceD)humanbeings(D)

9.Arobotcanbeusedtoexpandourfrontierswhen________.

A)itsintelligenceandcostarebeyondquestion

B)itisabletobeartheroughenvironment

C)itismadeascomplexasthehumanbrain

D)itsarchitectureisdifferentfromthatofthepresentones(A)

10.Itcanbeinferredfromthepassagethat________.

A)aftertheinstallationofagreatnumberofcellsandconnections,robotswillbecapableofself-reproduction

B)withtherapiddevelopmentoftechnology,peoplehavecometorealizethepossibilityofmakingamachinewithhuman-likeability

C)oncewemakeamachineascomplexasthehumanbrain,itwillpossesintelligence

D)robotswillhavecontrolofthevast,man-madeworldinspace