2021年托福试题阅读理解模拟题考点分析(卷七)

经典word整理文档，仅参考，双击此处可删除页眉页脚。本资料属于网络整理，如有侵权，请联系删除，谢谢！2021年托福试题阅读理解模拟题考点分析（卷七）Title：SocialityinAnimalsSocialinsectsrepresentthehighpointofinvertebrateevolution.Somespeciesliveincommunitiesofmillions,coordinatingtheirbuildingandforaging,theirreproduction,andtheiroffspringcare.Yetsocialityisfoundinonlyafewspeciesofinsects,andisrareamongvertebratesaswell:wildebeest(largeantelope)andlionsaretheexceptionratherthantherule.Nearlyallfish,amphibians,reptiles,birds,andmammalsaresolitary,exceptwhencourtingandmating.Birdsandmammalsusuallyreartheiryoung,butyear-roundfamilygroupsarealmostunknown,thoughtheyareintenselystudiedwheretheydoexist.Thesameistrueforinsects.Weknow,orthinkweknow,thatsocialgroupsaregood.Wolvesarebetterpredatorswhentheyhuntinpacks,andpigeonsescapefromfalconsfarmoreoftenwhenfeedinginflocks.Groupbuildingprojects—thedamsbeaversbuildtoblockabodyofwaterthatprovidesthemwithrelativesafetyfrompredatorsandthelodgestheybuildforshelter,for—canprovideahighlevelofprotectionandcomfort.Why,then,aresocialspeciessoveryrare?Infact,livingsociallypresentsinevitableproblemsthattranscendhabitatneedssothatonlywhenthesecostsareoffsetbycorrespondingbenefitsisgrouplivingaplus.Themostobviouscostiscompetition.Allthemembersofaspeciessharethesamehabitat;whentheylivetogether,theyaretryingtoeatthesamefoodandoccupythesamenestingsites.Ingeneral,thereisfarlesscompetitionawayfromagroup,andselectionshouldfavoranyindividualwho(allthingsbeingequal)setsoffonitsown,leavingthemembersofitsgroupbehindtocompeteamongthemselvesforlimitedresources.Anotherdifficultyisthatconcentrationsofindividualsfacilitatediseaseandparasitetransmission.Onthewhole,socialanimalscarrymoreparasitesandspecies-specificdiseasesthandosolitaryanimals.Parasitesanddiseasesdiminishthestrengthandlimitthegrowthofanimals,andamonghighlysocialcreatures,epidemicscandevastatewholepopulations.Distemper(aviraldisease)hasbeenknowntowipeoutentirecoloniesofseals,forinstance.Sothepenaltyofsociallifeispotentiallyhuge.Butinsomeinstances,thepayoffscanbeevengreater.Twohavealreadybeenmentioned:cooperativehuntinganddefensivegroups.Socialhuntingislikelytoevolvewherepreyistoolargetobetakenbyindividualsoperatingalone.Tocapturewildebeestsomemembersofagroupoflionsfollowtheirpreyandherdthemtowardotherslyinginambush.Inotherspecies,individualsforageorhuntsimultaneouslyandsharethefood.Vampirebatsthathavehadabadday,forinstance,arefedbymoresuccessfulmembersofthecommunity,buttheyareexpectedtoreturnthefavorinthefuture.Cooperationcaneveninvolvesharinginformationaboutthelocationoffood.Somecolonialbirds,suchasbankswallows,usethedeparturedirectionofasuccessfulforager(foodhunter)tolocateconcentrationsofprey.Informationtransfercanbeunintentionalthoughsomespeciesmakeuseofspecialassemblycallsorbehavior.Cooperationingroupdefense,suchasweseeincirclesofmuskoxenorelephants,isquiterareamongvertebratesbutisprevalentamongthesocialinsects.Thestrategyofemployingmanyeyestowatchfordanger,ontheotherhand,iswidespreadinbirdsandmammals.Aherdofgazelles(smallantelope)isfarmorelikelytospotalurkinglionoraconcealedcheetahthanisaloneindividual,andatagreaterdistance.Infact,agroupentersintoakindoftime-sharingarrangementinwhichindividualantelopealternatebitingoffamouthfulofgrasswithaperiodoferectandwatchfulchewing.Alargergroupcanaffordmorebitesperindividualperminute,therebeingmoreeyestoscanfordanger.Forasmallantelopelivinginaforestwherevisibilityislimited,however,remaininghiddenisprobablyabetterbetthanassemblingintonoisyherds.Amongthemillionsofspeciesofinsects,onlyafewthousandaresocial.ThoseraritiesaregenerallyconfinedtotermitesandHymenoptera.Alltermitesaresocial:theirdiet(cellulose)requiresthateachgenerationfeedaspecialkindofbacteriaorfungitothenextgenerationtoaidinitsdigestion.Ofthenumeroushymenopterans,someParagraph1Allanimalsthatreartheiryoungareconsideredtobesocial.Paragraph2offsetitscostsParagraph3Themostobviouscostiscompetition.Allthemembersofaspeciesintensecompetitionforresourcesamongindividualsapartfromagroup.Naturalselectionfavorslivingapartbecauseindividualsareunlikelytoattracttheattentionofpredators.Naturalselectionfavorslivingapartbecausegroupliving4.Theword"devastate"inthepassageisclosestinmeaningtoalterdestroyinvolve标题社会性的动物只有少数种类的昆虫存在社会性，而且在脊椎动物中也很罕见:羚羊大羚羊和狮子是例外，而不是规则。几乎所有的鱼、两栖动物、爬行动物、鸟类和哺乳动物都是孤独的，除非是在求爱和交配的时候。为人知的，尽管它们的研究对象确实存在。昆虫也是如此。我们知道，或者认为我们知道，社会群体是好的。狼是更好的捕平的保护和舒适。那么，为什么社会物种如此稀有呢?事实上，在社成本被相应的利益抵消时，才会有一群人活得更久。;所有的事物都是平等的自己出发，让集团的成员在有限的资源中相生物中，流行病会毁灭整个种群。犬瘟热一种病毒性疾病已经被认为可以消灭所有的海豹群体，例如。因此，社会生活的惩罚可能是巨大的。但在某些情况下，回报可能更大。其中有两个已经被提及:合作行动。为了捕获角马，一些狮子跟随它们的猎物，把它们赶到埋伏的地方。在其他物种中，个体觅食或同时捕食并分享食物。例如，那些地的鸟类，如河岸燕子，利用一个成功的觅食者食物猎人的离开方殊的集合调用或行为。动物中很少见，但在群居昆虫中很普遍。另一方面，用许多眼睛来观察危险的策略在鸟类和哺乳动物中很普遍。一群瞪羚小羚羊更有可更远。事实上，一个群体进入了一种分时的安排，在这种安排中，每更大的群体每分钟可以承受更多的叮咬，有更多的眼睛去扫描危险。聚集在喧闹的羊群中要好得多。局限于白蚁和膜翅目昆虫。所有白蚁都是社会性的它们的饮食纤维素)要求每一代都为下一代提供一种特殊的细菌或真菌以帮助消化。蜂和黄蜂，但许多都是独居的。本条第一款万计的群体中，协调它们的建筑和觅食、繁殖和后代的照料。然而，只有少数种类的昆虫存在社会性，而且在脊椎动物中也很罕见:羚羊大羚羊和狮子是例外，而不是规则。几乎所有的鱼、两栖动物、爬行动物、鸟类和哺乳动物都是孤独的，除非是在求爱和交配的时候。鸟类和哺乳动物我们类别：农业类真题140316CN-P3TitleAgriculturalSocietyinEighteenth-CenturyBritishAmericaInthenorthernAmericancolonies,especiallyNewEngland,tight-knitfarmingfamilies,organizedincommunitiesofseveralthousandpeople,dottedthelandscapebythemid-eighteenthcentury.NewEnglandersstakedtheirfutureonamixedeconomy.Theyclearedforestsfortimberusedinbarrels,ships,houses,andbarns.Theyplumbedtheoffshorewatersforfishtofeedlocalpopulations.Andtheycultivatedandgrazedasmuchofthethin-soiled,rockyhillsandbottomlandsastheycouldrecoverfromtheforest.Thefarmersofthemiddlecolonies-Pennsylvania,Delaware,NewJersey,andNewYork-settheirwoodenplowstomuchrichersoilsthanNewEnglandersdid.TheyenjoyedtheadditionaladvantageofsettinganareaalreadypartlyclearedbyNativeAmericanswhohadreliedmoreonagriculturethanhadNewEnglandtribes.Thusfavored,mid-Atlanticfarmfamiliesproducedmodestsurplusesofcorn,wheat,beef,andpork.Bythemid-eighteenthcentury,shipsfromNewYorkandPhiladelphiawerecarryingthesefoodstuffsnotonlytotheWestIndies,alwaysaprimarymarket,butalsotoareasthatcouldnolongerfeedthemselves-England,Spain,Portugal,andevenNewEngland.IntheNorth,thebroadownershipoflanddistinguishedfarmingsocietyfromeveryotheragriculturalregionoftheWesternworld.Althoughdifferencesincircumstancesandabilityledgraduallytowardgreatersocialstratification,inmostcommunities,thetrulyrichandterriblypoorwerefewandthegapbetweenthemsmallcomparedwithEuropeansociety.Mostmenotherthanindenturedservants(servantscontractedtoworkforaspecificnumberofyears)livedtopurchaseorinheritafarmofatleast50acres.Withtheirfamily’slabor,theyearnedadecentexistenceandprovidedasmallinheritanceforeachoftheirchildren.Settlersvaluedlandhighly,forowninglandordinarilyguaranteedbotheconomicindependenceandpoliticalrights.Bytheeighteenthcentury,amidwidespreadpropertyownership,arisingpopulationpressedagainstalimitedlandsupply,especiallyinNewEngland.Familyfarmscouldnotbedividedandsubdividedindefinitely,forittookatleastfiftyacres(ofwhichonlyaquartercouldusuallybecropped)tosupportasinglefamily.InConcurd,Massachusetts,forexample,thefoundershadworkedfarmsaveragingabout250acres.Acenturylater,inthe1730s,theaveragefarmhadshrunkbytwothirds,asfarmownersstruggledtoprovideaninheritanceforthethreeorfoursonsthattheaveragemarriageproduced.ThedecreasingfertilityofthesoilcompoundedtheproblemofdwindlingfarmsizeinNewEngland.Whenlandhadbeenplentiful,farmersplantedcropsinthesamefieldforthreeyearsandthenletitliefallow(unplanted)inpasturesevenyearsormoreuntilitregaineditsfertility.Butonthesmallerfarmsoftheeighteenthcentury,farmershadreducedfallowtimetoonlyayearortwo.Suchintenseuseofthesoilreducedcropyields,forcingfarmerstoplowmarginallandorshifttolivestockproduction.ThediminishingsizeandproductivityoffamilyfarmsforcedmanyNewEnglanderstomovetothefrontieroroutoftheareaaltogetherintheeighteencentury."Manyofouroldtownsaretoofullofinhabitantsforhusbandry,manyofthemlivingonsmallsharesofland,"complainedonewriter.InConcurd,oneofeveryfouradultmalesmigratedfromtowneverydecadefromthe1740son,andinmanytownsmigrationoutwasevengreater.SomedriftedsouthtoNewYorkandPennsylvania.Otherssoughtopportunitiesasartisansinthecoastaltownsortooktothesea.Moreheadedforthecolonies,westernfrontierornorthintoNewHampshireandtheeasternfrontierofMaine.SeveralthousandNewEnglandfamiliesmigratedevenfarthernorthtotheAnnapolisValleyofNovaScotia.ThroughoutNewEnglandaftertheearlyeighteenthcentury,mostfarmers'sonsknewthattheirdestinylayelsewhere.Wherevertheytookupfarming,northerncultivatorsengagedinagriculturalworkroutinesthatwerefarlessintensethaninthesouth.Thegrowingseasonwasmuchshorter,andthecultivationofcerealcropsrequiredincessantlaboronlyduringspringplantingandautumnharvesting.Thislessburdensomeworkrhythmletmanynortherncultivatorstofillouttheircalendarswithintermittentworkasclockmakers,shoemakers,carpenters,andweavers.PassageOne学科分类：History题目：ThecollapseofCopan本文共。第1段讲了Mayan的Copan衰落的第一个原因可能是thekingderivedfromcommerce第2段讲trade的兴衰对于Copan3段讲到干旱thedrought可能也是使其衰落的原因之一词汇题：1.abrupt=sudden2.derived=obtained3.core=center4.presumed=supposedPassageTwo学科分类：古生物学题目：Sauropodsskeletalinnovation本文共41段引出人们印象中大部分sauropods是前肢短小，可以直立的。第2段讲到不是所有的S都是直立的，一部分前肢和后肢差不多长，而且前后肢离身体中心比较开的一般不是直立3变得中空。第3段讲到虽然骨头中空，但是如何不会变得week词汇题：1.stance=imately=closely3.hollow=emptyPassageThree学科分类：生物学题目:WhyPaleozoicInsectsweresolarge本文共4段。第1段提出Paleozoic之前大气含氧量不是很大;第2段讲到Paleozoic含氧量大大提升，因此insects可以吸收更多氧气，所以变得更大。第3段讲到airgotdenser所以更多insects可以飞第4段讲到为什么insectslimit词汇题：1.attributeto=associatewith2.critical=essential3.allowedfor=madepossible4.successive=followingTitle：LivePerformanceUnlikevideoandcinema(althoughsometimesemployingelementsofboth),thetheaterisaliving,real-timeevent,withbothperformersandaudiencemutuallyinteracting,eachawareoftheother'simmediatepresence.Thisturnsouttobeanextremelyimportantdistinction.Distinguishedfilmstars,particularlythosewiththeaterbackgrounds(asmosthave),routinelyreturntothelivedramaticstagedespitethesubstantiallygreaterfinancialrewardsoffilmworkandinvariablypreferstageactingbecauseoftheimmediateaudienceresponsetheaterprovides,withitscorrespondingsensationsofexcitementandpresence.Thefirstoftheseistherapportexistingbetweenactorandaudience.Botharebreathingthesameair;bothareinvolvedatthesametimeandinthesamespacewiththestagelifedepictedbytheplay.Sometimestheirmutualfascinationisalmostpalpable;everyactor'sperformanceisaffectedbythewaytheaudienceyieldsorwithholdsitsresponses:itslaughter,sighs,applause,gasps,silences.Livetheatricalperformanceisalwaysatwo-waycommunicationbetweenstageandhouse.Second,theatercreatesarelationshipamongtheaudiencemembers.Havingarrivedatthetheatersasindividualsoringroupsoftwoorthree,theaudiencemembersquicklyfindthemselvesfusedintoacommonexperiencewithtotalstrangers:laughingatthesamejokes,empathizingwiththesamecharacters,experiencingthesamerevelations.Thisbroadcommunalresponseisneverdevelopedbytelevisiondrama,whichisplayedchieflytosolitaryorclusteredviewerswho(becauseoffrequentcommercialadvertisements)areonlyintermittentlyengaged,norisitlikelytohappeninmoviehouses,whereaudiencemembersessentiallyassumeaone-on-onerelationshipwiththescreenandrarely(exceptinprivateorgroupscreenings)breakoutinapowerfulcollectiveresponse,muchlessapplause.Bycontrast,livetheatricalpresentationsgenerateaudienceactivitythatisbroadlysocialinnature:thecrowdarrivesatthetheaterataboutthesametime,peoplemingleandchatduringintermissions,andalldeparttogether,ofteninspiritedconversationabouttheplay.Moreover,theycommunicateduringtheplay:laughterandapplausebuilduponthemselvesandgainstrengthfromtherecognitionthatothersarelaughingandapplauding.Thefinalovationuniquetoliveperformanceinevitablyinvolvestheaudienceapplaudingitself,aswellastheperformers,forunderstandingandappreciatingthetheatricalexcellencetheyhaveallseentogether.Andplayswithpoliticalthemescanevengeneratecollectivepoliticalresponse.Inacelebratedexample,1935sWaitingforLeftywasstagedasiftheaudiencewereagroupofunionmembers;bytheplay'sendtheaudiencewasyellingStrike!Strike!inresponsetotheplay'sissues.Obviously,onlyaliveperformancecouldevokesucharesponse.Finally,liveperformanceinevitablyhasthequalityofimmediacy.Theactionoftheplayistakingplacerightnow,asitisbeingwatched,andanythingcanhappen.Althoughinmostprofessionalproductionsthechangesthatoccurinperformancefromonenighttoanotheraresosubtlethatonlyanexpertwouldnotice,thefactisthateachnight'spresentationisunique,andeveryonepresenttheaudience,thecast,andthosebehindthescenesknowsit.Thisawarenesslendsanexcitementthatcannotbeachievedbytheatricaleventsthatarewhollyinthecan.Onereasonfortheexcitement,ofcourse,isthatinliveperformance,mistakescanhappen;thispossibilityoccasionsacertainabidingtension,perhapsevenanedgeofstagefright,whichsomepeoplesaycreatestheultimatethrillofthetheater.Butjustasdisastercancomewithoutwarning,sotoocansplendor.Onanygivennight,eachactoristryingtobetterhisorherpreviousperformance,andnooneknowswhenthiscollectiveeffortwillcoalesceintosomethingsublime.Theactors'constantstrivingtowardselftranscendencegivesthetheateravitalitythatismissingfromperformancesfixedunalterablyonvideotapeorcelluloid.Butperhapsmostappropriately,theimmediacyofliveperformanceembodiesthefundamentaluncertaintyoflife.Oneprimefunctionoftheateristoaddresstheuncertaintiesofhumanexistence,andtheveryformatofliveperformancepresentsamoment-to-momentuncertaintyrightbeforeoureyes.Ultimately,thisimmediatetheaterhelpsusdefinethequestionsandconfusionsofourlivesandletsusgrapple,inthepresent,withtheirimplications.1.TheworddistinctioninthepassageisclosestinmeaningtoA.ideaB.blendC.definitionD.difference2.Paragraph1makeswhichofthefollowingpointsabouttheaterandfilmA.Theateraudiencestendtobemorecriticalthanfilmaudiences.B.Actorsinthetheaterareusuallynotaswell-knownasfilmactors.C.Theatercompaniestendtopaymorethanfilmcompaniesdoforthemostdistinguishedactors.D.Audiencesrespondtoactorsdifferentlyintheaterthaninfilm.3.Paragraph1suggeststhatthereasondistinguishedfilmstarsreturntolivetheateristhattheyA.areabletocommandhigherfeesaswell-knownactorsB.enjoytheexcitementofperformingbeforealiveaudienceC.havegreatrespectfortheatricaldramaasanartformD.aredissatisfiedwiththerolestheyareofferedinfilmsandtelevision4.ThewordrapportinthepassageisclosestinmeaningtoA.excitementB.balanceC.bondD.fascination5.Inparagraph3,whichofthefollowingismentionedassupportforthestatementthatThisbroadcommunalresponseisneverdevelopedbytelevisiondramaA.Televisiondramaisrarelyaboutserioussocialissues.B.Peopledonotusuallytalktoeachotherwhilewatchingtelevision.C.Televisionaudiencesvarygreatlyintheirinterestintelevisiondramas.D.Peopledonottypicallywatchtelevisioninlargegroups.6.Accordingtoparagraph3,moviehouseaudiencesaredifferentfromaudiencesatlivetheatricalperformancesbecausemoviehouseaudiencesdonotA.enjoyhumorandjokesasmuchastheateraudiencesdoB.developbroadcommunalresponsesC.sympathizewiththecharacterstheyseedramatizedD.generallyapplaudunlesseveryoneelseisapplauding7.WhydoestheauthormentiontheplayWaitingforLeftyA.ToillustratethepowerofthecommunalresponsetoplaysB.ToarguethatplaysaboutpoliticalsubjectshavemorepowertoevokedeepfeelingsinanaudiencethannonpoliticalplaysdoC.ToprovideanexampleofaplaythatwasapopularsuccessbecauseitdealtwithimportantpoliticalissuesD.Tocomparethepoliticalimportanceofplaysinrecenttimeswiththepoliticalimportanceofearlierplays8.Whichofthesentencesbelowbestexpressestheessentialinformationinthehighlightedsentenceinthepassage.Incorrectchoiceschangethemeaninginimportantwaysorleaveoutessentialinformation.A.Althoughexpertscandetectthechangesthatoccurindifferentperformances,thechangesaretoosubtletobenoticedbyanyoneelse.B.Althoughtheirperformancesvaryonlysubtlyfromonenighttoanother,actorsinmostprofessionalproductionswantaudiencestobelievethateveryperformanceisunique.C.Everyoneinvolvedintheprofessionalproductionofaplayknowsthatverysmall,almostunnoticeablechangesmakeeachperformanceunique.D.Inmostprofessionalproductions,changesareincludedfromoneperformancetoanotherthatareintendedtomakeeveryperformanceauniqueone.9.ThewordthrillinthepassageisclosestinmeaningtoA.goalB.weaknessC.meaningD.excitement10.ThewordvitalityinthepassageisclosestinmeaningtoA.styleB.energyC.purposeD.quality11.Accordingtoparagraph4,onanygivennighttheresultofactors'effortstobettertheirpreviousperformancesisthattheactorsA.formlong-lastingrelationshipswiththeaudienceB.arebetterabletoovercometheirstagefrightC.createaqualitythatisnotpresentinfilmortelevisionD.aremorelikelytobeadmiredbyaudiences12.Itcanbeinferredfromparagraph4thatoneofthereasonsfilmedperformancesarelessexcitingthanlivetheatricalperformancesisbecauseA.thereislittlechancethatamistakewilloccurinafilmedperformanceB.mostmoviesportraysituationsthataudienceshaveseenbeforeC.audiencesareinterestedinseeingfamousactorsliveratherthanonascreenD.mostpeopleareaccustomedtogoingtothemoviesbutviewthetheaterasaspecialevent13.Lookatthefoursquaresthatindicatewherethefollowingsentencecouldbeaddedtothepassage.Suchsignsofanaudience'sengagementthusbecomepartofeveryperformance.Wherewouldthesentencebestfit?Clickonasquaretoaddthesentencetothepassage.题目不完整)14.Dragyourchoicestothespaceswheretheybelong.Toreviewthepassage,clickonViewText.AnswerChoicesA.Althoughlivetheaterisunlikeeithervideoorcinema,thedifferentgenressometimesoverlap.B.Whilelivetheaterisregardedbymostfilmactorsasthemostexcitingplacetoperform,manyaretootroubledbystagefrighttoperformlive.C.Inthetheater,thereisatwo-waycommunicationbetweenactorandaudiencethathasaneffectontheactor'sperformance.D.Audiencesatlivetheatricalperformancesformaspecialconnection,sharingthecommonexperienceofreactingtoalivetheatricalperformance.E.Manypeoplegotothetheaterexcitedtoseeinaliveperformanceanactorthattheyhaveneverseenbeforeexceptontelevisionorinfilms.F.Theexcitementoflivetheatercannotbeachievedinanyothermedium,anditsimmediacyanduncertaintyhelpusdealwithlife'sfundamentaluncertainty.Title：ExtinctionsattheEndoftheCretaceousIthaslongbeenrecognizedthatthedinosaursdisappearedfromthefossilrecordattheendoftheCretaceousperiod(65millionyearsago),andasmoreknowledgehasbeengained,wehavelearnedthatmanyotherorganismsdisappearedataboutthesametime.Themicroscopicplankton(free-floatingplantsandanimals)withcalcareousshellssufferedmassively.Thefoundationofthemajormarinefoodchainthatledfromtheminuteplanktontoshelledanimalstolargemarinereptileshadcollapsed.Onlanditwasnotonlythelargeanimalsthatbecameextinct.Themammals,mostofwhichweresmall,lostsome35percentoftheirspeciesworldwide.Plantswerealsoaffected.Forexample,inNorthAmerica79percentdidnotsurvive,andithasbeennotedthatthesurvivorswereoftendeciduoustheycouldlosetheirleavesandshutdownwhileotherscouldsurviveasseeds.Asinthesea,itseemsthatonthelandonekeyfoodchaincollapsed:theonewithleavesasitsbasicrawmaterial.Theseleaveswerethefoodofsomeofthemammalsandoftheherbivorousdinosaurs,whichinturnwerefedonbythecarnivorousdinosaurs.Furthermore,itismostlikelythattheselargedinosaurshadslowratesofreproduction,whichalwaysincreasestheriskofextinction.Crocodiles,tortoises,birds,andinsectsseemtohavebeenlittleaffected.Thetwofirstnamedareknowntobeabletosurviveforlongperiodswithoutfood,andbothcanbescavengers(feedondeadmaterial).Indeed,withthedeathsofsomanyotheranimalsandwithmuchdeadplantmaterial,thefoodchainbasedondetrituswouldhavebeenwell-supplied.Manyinsectsfeedondeadmaterial;furthermore,mosthaveatleastonerestingstageinwhichtheyareveryresistanttodamage.Inunfavorableconditionssomemaytakealongtimetodevelop:thereisarecordofabeetlelarvalivingindeadwoodforover40yearsbeforebecominganadult.Somebirdswerescavengers,butthesurvivalofmanylineagesisapuzzle.WhathappenedinthebiologicalstoryjustaftertheseextinctionswhatisfoundinandjustabovetheboundarylayerbetweenthedepositsoftheCretaceousandthoseoftheTertiary(65¨C2.6millionyearsago),termedtheK/TboundaryForaveryshortperiodthedominantmicroorganismsinmarinedepositswereusuallydiatomsanddinoflagellates(bothsingle-celledtypesofplankton).Theimportantfeatureforthesurvivalofboththesegroupswastheabilitytoformprotectivecysts(sacsaroundorganisms)thatrestedontheseafloor.Abovethese,inthelaterdeposits,aretheremainsofotherminuteplankton,butthetypesarequitedifferentfromthoseoftheLateCretaceous.Interrestrialdepositsasuddenanddramaticincreaseinfernplantsporesmarkstheboundaryinmanypartsoftheworld;fernsareearlycolonizersofbarrenlandscapes.Thefernspike(suddenincrease),asitistermed,hasbeenfoundalsoinsomemarinedeposits(suchwastheabundanceoffernsporesblownaroundtheworld),anditoccursinexactlythesamelayerofdepositwheretheplanktondisappear.Wecanconcludethatthemajormarineandterrestrialeventsoccurredsimultaneously.Manytheorieshavebeenputforwardfortheextinctionofthedinosaurs,butmostofthemcanbedismissed.Since1980therehavebeenmorefocused,butstillcontroversy-ridden,investigations.InthatyearLouisandWalterAlvarezandcolleaguesfromtheUniversityofCaliforniapublishedtheirresearchontheamountsofvariousmetalsintheboundarybetweenCretaceousandTertiaryrocks(K/Tboundary)inItaly,Denmark,andNewZealand.Theyhadfound,accidentally,thatararemetal,iridium,suddenlybecameveryabundantexactlyattheboundaryandthenslowlyfellaway.Thisphenomenon,knownastheiridiumspike,hasnowbeenidentifiedinK/Tboundarydepositsinoverahundredothersitesintheworld.Iridiumoccursinmeteoritesandvolcanicmaterial,butinthelattercaseitisaccompaniedbyelevatedlevelsofnickelandchromium.TheseothermetalsarenotespeciallyabundantattheK/Tboundary.TheAlvarezesconcludedthattheiridiumspikewasduetoalargeasteroidthatstruckEarth65millionyearsago.1.ThewordrecognizedinthepassageisclosestinmeaningtoA.suspectedB.arguedC.assumedD.accepted2.Accordingtoparagraph1,whichofthefollowingwastrueofsmallplanktonicorganismsattheendoftheCretaceousA.Theylosttheirmainsourcesoffood.B.Theydevelopedcalcareousshells.C.Theydecreasedgreatlyinnumberasdidmanyothertypesoforganisms.D.Theyreplacedotherminuteorganismsasafoodsourceinthemajormarinefoodchain3.WhichofthefollowingstatementsisNOTsupportedbytheinformationprovidedinparagraph2aboutextinctionsattheendoftheCretaceousA.About35percentofmammalspecieswerelost.B.79percentofNorthAmericanplantsdisappeared.C.Mostbirds,tortoises,andcrocodilesescapedextinction.D.Deciduoustreeswereespeciallylikelytogoextinct.4.Accordingtoparagraph2,whichofthefollowingfactorsprobablycontributedtotheextinctionofthedinosaursA.ThelengthoftimeittookdinosaurstoreproduceB.LargequantitiesofdeadmaterialdisturbingtheirhabitatsC.IncreasedcompetitionforfoodfromscavengersD.Anincreaseincarnivorepopulations5.Inparagraph2,whydoestheauthorprovidetheinformationthatthereisarecordofabeetlelarvalivingindeadwoodforover40yearsbeforebecominganadultA.TohelpexplainwhyinsectswerelesslikelytogoextinctthanotherspeciesB.ToshowthatnotallspeciesthatreliedontreesdisappearedduringthelateCretaceousC.TosuggestthatinsectsthatlivedlongagohadmuchlongerlifespansthanthoselivingtodayD.TosupporttheclaimthatconditionsattheendoftheCretaceouswerehighlyunfavorable6.ThewordsimultaneouslyinthepassageisclosestinmeaningtoA.rapidlyB.repeatedlyC.atthesametimeD.fordifferentreasons7.Accordingtoparagraph3,whichofthefollowingistrueofplanktonaftertheextinctionsattheendoftheCretaceousA.Diatomsanddinoflagellatessuddenlybecameveryrare.B.Single-celledtypesofplanktonwerereplacedbymorecomplicatedmicroorganisms.C.Theplanktonfoundinlaterdepositsarecloselyrelatedtosingle-celledLateCretaceousmicroorganisms.D.TheonlytypesofLateCretaceousplanktontosurviveextinctionwerethoseprotectedbyc