2015-2012年电子科技大学硕士研究生英语分级考试PlacementTest带答案

PAGEPAGE6PlacementTestforGraduateStudentsAugust,2015本分级测试主要检测学生英语水平、语言能力和批判性思维能力，为英语教学分班提供依据，望同学们认真答题，体现出自己真实水平。本测试同时也为教师教学提供参考，测试成绩按一定比例计入平时成绩。本测试时长共90分钟。测试对速度有一定要求，同学们可参考各部分建议，合理分配答题时间。第1~30题为听力，请用耳机收听。所有答案做在机读卡上。试卷请妥善保管，开学第一周带到课堂。PARTI LISTENINGCOMPREHENSION(30minutes,30points,1pointeach)SectionADirections:Inthissection,youwillhear9shortconversationsbetweentwospeakers.Attheendofeachconversation,aquestionwillbeaskedaboutwhatwassaid.Theconversationsandthequestionswillbereadonlyonce.ChoosethebestanswerfromthefourchoicesgivenbymarkingthecorrespondingletterwithasinglebaracrossthesquarebracketsonyourmachinescoredAnswerSheet.1. A.Itwaswet. B.Itwastorn.C.Itwasdirtywithdust . D.Itwasblood-stained. 2. A.Doctorscandonothingabouthisproblem. B.Itistoosmallaproblemtogettreated. C.Healthcareisveryexpensive. D.Doctorscanfixhisproblem.3. A.Smokingisstupid.B.Smokingonecigaretteisenough.C.Smokinginpublicplacesisoffensive.D.Smokingiscool.4. A.Rememberthisplace. B.Moveaheadwiththeline. C.Answerthecall. D.Comebackquickly.5. A.Hedoesn’tdrinkteaveryoften. B.HeisnotinterestedinPekingopera. C.HeknowsnothingaboutPekingopera. D.HeenjoyswatchingPekingopera.6. A.885-450-4310 B.848-405-3140 C.858-405-3410 D.405-858-34107. A.She’llhelpthemanoutofthetrouble. B.Themanhasalwaysbeenintrouble. C.Nooneelsewillhelpthemanexceptherself. D.Shedoesn’twanttheirrelationsmentioned.8. A.Johnwillnotstayinjailforalongtime. B.Johnisafamilymemberwithabadreputation. C.Johnhasbeendrivenoutofthefamily. D.John’sjobdiffersfromthatofhisfamilymembers.9. A.Shedislikesthesmellinthehouse. B.Shesmellssomethingburn. C.Sheisafraidthatthehouseisonfire. D.Shefeelssomethingiswrong.SectionBDirections:Inthissection,youwillhear3conversations.Attheendofeachconversation,questionswillbeaskedaboutwhatwassaid.Theconversationsandthequestionswillbespokenonlyonce.ChoosethebestanswerfromthefourchoicesgivenbymarkingthecorrespondingletterwithasinglebaracrossthesquarebracketsonyourmachinescoredAnswerSheet.ConversationOneQuestions10to14arebasedontheconversationyouhavejustheard.10.Whatisthepurposeoftheconversation?A．Thewomanwantstomakeanappointmentwiththelibrarian.B．Thewomanistryingtoreserveabookforherclassmate.C．Thewomanisinquiringabouttheavailabilityofstudyrooms.D．Thewomanwantstoreserveadifferentroominthelibrary.11.Listenagaintopartoftheconversation.Thenanswerthequestion.Whydoesthemansaythis:A．ToinformthewomanthatnoroomsareavailableB．ToencouragethewomantoreservearoomnowC．TorecommendtheroomsonthethirdfloorD．Toletthewomanknowwhichroomsarebetter12.Accordingtotheman,whyaresofewstudyroomsavailable?A．Therearemorestudentsnowthaninthepreviousyear.B．Severalroomsarebeingusedasofficesforlibrarystaff.C．Thereisaproblemwithstudentsreservingmorethanoneroom.D．Someoftheuniversitybuildingsarestillunderconstruction.13.Whydoesthewomanneedastudyroom?A．Sheispreparingforafinalexamination.B．Herprofessorrequireseveryonetohaveastudyroom.C．Shedoesnothavespacetostudyinherapartment.D．Sheneedsaplacetomeetwithotherstudents.14.Whydoesthemansaythis:A.Theyareagroupofpeoplewhocometogethermainlyforamusement.B.Theyorganizevotersandcompeteforsupportonmajorissues.C.Theyarevoluntaryorganizationsofpeoplewhoagreeonpublicpolicies.D.Theyhaveresearchofficesthatdeveloppositionsonimportantissues.29.Whatdoestheprofessormeanwhenhesaysthis:A．Itispossibletoenjoypoliticsbutdislikegovernmentatthesametime.B．Apoliticalpartycaresaboutmajorissues,butagovernmentdoesn'tcare.C．Politicsisaboutcompetition,whilegovernmentisaboutresponsibility.D．Electionsandgovernmentareliketwosidesofthesamecoin.30.Whydoestheprofessorsaythis:A．Toshowhowmajorpartiesusuallydealwiththesameissues.B．Tosuggestthatbothpartiesshouldgiveeducationmoreattention.C．Tocontrastthephilosophyandmethodsofopposingparties.D．Topointoutwhichpartyismoreconcernedwitheducation.PARTII Grammar(10minutes,10points,1pointeach)Directions: Therearetensentencesinthissection.Readeachsentencecarefully.Ifthereisanerror,selecttheunderlinedpartthatisincorrect.Ifthereisnoerror,chooseanswerD.Markthecorrespondingletterwithasinglebaracrossthesquarebracketsonyourmachine-scoringAnswerSheet.31.Thepresenceofstrongfeeling,thecauseofwhich(A)isnotfullyunderstood,alwayshastheeffect(B)ofmakingwe(C)humanbeingsuneasy.Noerror(D)32.Idonotwishtomake(A)aformalcomplaint,butIwouldhavebeenbetterpleasedifyougave(B)theawardtothepersonwho(C)bestdeservedit.Noerror(D)33.Thetribesmenmadeofferingstoplacate(A)thegods,whom(B)theybelieved,were(C)angrywiththem.Noerror．(D)34.Fromancienttimes(A),sculpturehadbeen(B)consideredtheprerogativeofmen,andevennow,insomepartsoftheworld,womensculptorsface(C)hostilityandsuspicion.Noerror(Ｄ)35.AccordingtoHume,itisnotlogicandreasoningthat(A)determine(B)ouractions,but(C)emotion.Noerror.(D)36.Thegeneralreportedthat(A),asaresultof(B)financialconstraints,less(C)soldierswouldbesentonpeace-keepingmissionsthisyear.Noerror.（D）37.Theornatepillarsandlife-size（A）statuesthatthemagnatehaschosen(B)toadornhisswimmingpoolarelikeaGreektemple(C).Noerror.(D)38.Afteryouhavewritten(A)adefinitioninyourvocabularynotebook,addafew(B)waystousethewordorasentencetoillustrateit's(C)meaning.Noerror.(D)39.Theracingchampionhad（Ａ）madenomention（Ｂ）inhisspeechofthemechanicsonwhom（Ｃ）hissuccesshaddepended.Noerror.（Ｄ）40.Thenewlawistoo（Ａ）stringent;itwillbe（Ｂ）neitherrespectedor（Ｃ）obeyed.Noerror.（Ｄ）PARTIII CriticalReading(50minutes,30points,1pointeach)Directions: Choosethebestanswerfromthefourchoicesgivenandmarkthecorrespondingletterwithasinglebaracrossthesquarebracketsonyourmachine-scoringAnswerSheet.1 Whilevirtuallyallscientistsaccepttheprinciplesofevolutionarytheory,thereremainsgreatuncertaintyconcerningthemechanismofrapidanddrasticchangebetweensuccessivespecies.Inthepast,interspecieshybridizationwasdismissedasapossiblesolution,sincehybridsarerarelyasvigorousaspurebredspecies.However,currentresearchonhybridizationsuggeststhatalthoughsomehybridsarenotasvirileaseitheroftheparentspecies,theyareoftenstrongenoughtopasstheirtraitson.Scientistshavealsofoundhybridspecies,suchascertaintypesofcorn,thatarestrongerthantheirparentspecies,aphenomenonknownas“hybridvigor”.Thesefindingssuggestthathybridizationplaysafarmoreimportantroleinevolutionthanpreviouslysuspected.41.Itcanbeinferredthatsomescientistspreviouslybelievedthat________.A.thedetailsofevolutionarytheorymayneverbefullyunderstoodB.hybridplantslacktheabilitytoreproducebythemselvesC.plantsthatarerobustpossessanevolutionaryadvantageD.purebredplantsplayarelativelyminorroleinevolution42.Thepassageimpliesthatmostscientistswilladoptatheorythat________.A.includeselementsaboutwhichlittleisknownB.cannotbeprovenbyexperimentalmeansC.involvesideaswhichwilllikelybedisprovedlaterD.haslimitedreal-worldapplications2 Thoughmostpeopleknowthedefinitionoftheword“boycott”,fewknowitsorigin.NamedforCaptainCharlesBoycott,thewordasweknowitoweslesstohimthantoIrishnationalistCharlesParnell.ParnellorganizedIrishfarmersandconvincedthemtofixtheirrentrates.WhenBoycottrefused,Parnellunleashedthepowerofthepeople.AbandofhostilepeasantsforcedtheCaptain’sservantstoleave.Therewerenolaborerstogathertheharvestandnostablementocarefortheanimals.Boycottwasnotallowedtoenterstoresormakepurchases.Eventually,BoycottandhiswifefledIreland,andParnellwashailedastheworkingman’shero.43.Thepassageisbestsummarizedbywhichofthefollowing?A.Theoriginofawordisexplored,andanexplanationforitspopularityisgiven.B.Awordisintroduced,andahistoryofitsusageisrelated.C.Aneventisdescribedasthereasonbehindashiftinaword’smeaningD.Awordisintroduced,andthehistoryofitscoiningisrelated.44.Itcanbemostreasonablyinferredfromthepassagethat_______.A.Boycott’slandwasnotharvestedthatyearB.thetownspeoplereferredtoweresympathetictothefarmersC.ParnellwaspopularamongallIrishmenD.thefarmersthreatenedBoycottwithphysicalharm3Passage1: NomajorpoliticalelectionintheUnitedStateshaseverbeendecidedbyonevote.Infact,asinglevotecontributesonlyaboutonemillionthofthetotalresultoftheaveragestatewideelection.Consideringhownumericallyinsignificantasinglevoteis,isthereanyrationaljustificationforanindividualtovote?Inordertoanswerthisquestion,onemustlookpastthemerenumericalvalueofavote.Anindividual’svoteisvaluableasameasureofthatindividual’sbeliefinthesystemofgovernment,whichlikewiseindicatesthedegreetowhichapersonfeelsincludedinthegreatersocialorder.Passage2: Whenrecentlyaskedwhomhevotedforinthelastpresidentialelection,afriendofminereplied,“Ididn’tbother.”Witharatherboredshrug,andlittleembarrassment,myfriendcontinued,“It’snotlikeitmatters.Myvotewouldn’thavechangedtheoutcome.”Icouldn’thelpthinkingthenthattheargumentwasuncannilypersuasive.IfIhadstayedinbedthatmorning,theresultwouldlikewisebeexactlythesame.Buttheargumentdoesnotholdupunderscrutiny.Ifdemocracymeansrulebythepeople,andnotbyanyoneindividual,thenwhyshouldthevoteofjustonepersondeterminetheoutcomeofanelection?Noperson,nomatterwhoheis,shouldbeabletochangethegreaterwillofacollectedgroup.Theideaofdoingsoissimplyundemocratic.45.Whichofthefollowing,iftrue,wouldmoststrengthenthehypothesisoftheauthorofPassage1concerningvotingbehavior?A.Historicaldocumentsrevealthatmaylocalelectionshavebeendecidedbyasinglevote.B．AnewstudyfindsthatmanyAmericansfeelthatvotingisaburdensomeinconvenience.C．ApollofAmericancitizensindicatesthatmostcitizensconsidervotinganimportantcommunalduty.D．Votingrecordsshowthatmostpeoplewhovoteparticipateinbothnationalandlocalelections.46.TheauthorofPassage1wouldmostlikelyconcludewhichofthefollowingaboutthe“friend”describedinPassage2?A.Thefriendlikelyfeelsthatheisdisconnectedfromthesocietyinwhichhelives.B．Unlesshechangestheoutcomeofanelection,thefriendisunlikelytoevervote.C.Thenumberofpeopletodaywhoactasthefrienddoesindicatesafundamentalflawinsociety.D．Peoplewhodon’tfeeltheneedtovotearegenerallysatisfiedwithlifeasitis.47.Bothpassagesservetodiscouragethe________.A．inclinationofAmericanstoinventexcusesfornotvotingB．tendencyofvoterstoavoidmakingdifficultdecisionsC．valuationofavotebyitsabilitytodecideanelectionD．apathythatsomevotersfeelaboutthelackofrealchoices48.ThefinalsentenceofPassage2servesto________.A．explaintherationalebehindabehaviorpatternB．denouncetheactionsofthosewhodonotvoteC．showthesubtleironyofthefriend’sargumentD．offerasolutiontoapressingproblem41 Laboratoryresearchisattheheartofscientificlife;scientists’realworkconsistsoftestingoutideasthatcometothemastheyponderthemysteriesoftheworldaroundthem.Anaturalbiologistwalksthroughacityparkoracrossasuburbanlawnandishalf-consciouslywondering:Whytwoleavesinsteadofthree?Whypinkflowersinsteadofwhite?Suchruminationgoesonwithoutendinascientist’smind,acontinuousaccompanimenttotherhythmofdailylife.Whateverascientistisdoing—reading,cooking,talking,playing—sciencethoughtsarealwaysthereattheedgeofthemind.Theyarethewaytheworldistakenin;allthatisseenisfilteredthroughaneverpresentscientificmusing.2 Howawould-bescientistdecidesonadiscipline,settlesonaproblem,andgoestoworkisoftenasmuchamailerofchanceasitisoftemperament.Onecaneasilybecomeachemistoraneuroanatomistbecauseofwhereonewenttoschoolorwhoseinfluenceonehappenedtocomeunderasbecauseofacompellingearlyresponsetothelogicofchemistryorthebeautyofthehumannervoussystem.Nomatter.Oncethedisciplineisestablished,theproblemchosen,andthescientistimmersedinthework,heorshebecomesaspersuadedasneedbeofthecentralityandurgencyoftheparticularworkbeingdone.Suchadaptivemyopiaisnecessaryinsciencebecausethegrinding,repetitiveminutenessofdailylaboratoryworkissotime-consuming(forweeks,months,evenyearsatatime)that,often,eventoremembertheoriginalimpetusfortheworkisapsychologicaltrickofthehighestorder.Tostimulatethememorybackintoexistencewithfairregularity,onemustbelieveinthefundamentalimportanceofwhatoneisdoing.Thosewhodoarethemostenergetic,vital,exciting,andexcitedofscientists.3 CarolSteiner,ageneticist,comesupwithafinemetaphorforhowtomakeaworkingpropositionofscientificmystery.“Imagine,”shesays,“thatyouhaveajigsawpuzzlewithnopictureprintedonit.Allyouhavearepiecesyouhaven’tacluehowtomakesenseof.Thepiecesareyourseparatescientificobservations.Here’sanexampleofhowyoumighttrytogetahandleonthepuzzle:4 “Wehaveamicroorganismwithasecretorystructureononeend.Weknowthisstructureisalwaysonthesameplaceinthecellandthatthepositionofthisstructureisinherited.Thequestionwewanttoansweris,howcaninheritedinformationbetranslatedintopositionalinformation?Whyinthatoneplaceandnoplaceelse?Isthegeneticcodeinvolved,andifso,how?Theanswerwilltellushowthegenesworkinconcertwiththerestofthecelltoputthingswheretheybelong.5 “Inordertogatherpiecesofthejigsawpuzzle(thatis,piecesofinformation),wepokeatthecell.Wechangeitalittle….Aspecificmutationthatalteredthemembranestructureofthecellwasfoundtoturnoffthesynthesisofthesecretorystructure.Thiswasapieceofthejigsawpuzzle.Butjustonepiece.Becausewehadn’taclueastohowthishadhappenedorcouldhappen.”Steinerindicatesthattherewillbemanyfurtherquestionsthatwillsuggestexperimentswhoseresultsmayallowustoprintpicturesonthepiecesofthejigsawpuzzle:“Notputthepuzzletogether,mindyou.Buthelpusthinkaboutwhatthepicturewillultimatelylooklike.”6 TherealizedpictureonCarolSteiner’sjigsawpuzzleisthemapofgeneexpressionlaidoutclearlywithallroads,pathways,connectingsignalpoints,andrailwayjunctionsmarkedsothatanytouristcanfindhisorherwayinthisbeautifulcountry,whichisconfusingonlywhenoneiswanderingaboutinignorance—asweallarenow—withahighlyincompletemap.49.Theprimarypurposeofthepassageistoconveyinformationaboutthe________.A.occupationalhazardsencounteredbylaboratoryworkers.B.problem-solvingskillstaughtbychemistsandneuroanatomistsC.professionalcollaborationnecessaryforgeneticistsD.thoughtprocessesdistinctivetoresearchscientists50.InLine1,theauthorcharacterizes“laboratoryresearch”assomethingthatis________.A.fundamentalB.ambitiousC.challengingD.time-consuming51.Theauthorindicatesthattheprocessof“rumination”(paragraph1)is________.A.subjectiveB.vexatiousC.incessantD.innovative52.Inparagraph2,“Nomatter”dismissesasirrelevantthemeansbywhich________.A.sciencestudentslearnresearchskillsB.scientistschooseresearchspecialtiesC.laboratoryreportsexplainmethodologiesD.scientificknowledgeisperceivedbythepublic53.The“memory”referredtoinparagraph2isthatofthe________.A.initialfascinationwithascientificgoalB.stepsrequiredtoestablishscientifictruthC.day-to-dayrepetitivenessoftheworkD.relevanttrainingintheacademicfield54.Thepassageimpliesthatthediscoveryofthe“specificmutation”(paragraph5)wasmostsignificantfor________.A.demonstratingtherandomnatureofscientificbreakthroughsB.provingthatmultiplefactorsaffectmicroorganismsC.providingacluetothesolutionofaresearchquestionD.justifyingtheexpenseofamajorresearchproject55.WhichbestdescribesthefunctionofSteiner’saccountofherresearchintheoveralldevelopmentofthepassage?A.Adigressionfromtheauthor’scentralargumentB.ArefutationofcriticismsraisedearlierinthepassageC.AnobservationthatchallengespreviousassertionsD.Anexamplethatexpandsuponprecedinggeneralization51 Thedownslopemovementofrock,mud,orothermaterialundertheinfluenceofgravityisknownasmasswasting.Whiletheangleoftheslopeisamajorfactorinthepotentialformasswasting,theslopeisnotthesoledeterminerofmasswastingevents.Waterplaysasignificantrole,especiallywhereitisplentifulduringtherainyseason.Earthquakesmaycauserockslides,mudflows,andothermassmovements.Factorssuchasthepresenceorabsenceofvegetationandhumanactivitiescanalsoinfluencethepotentialformasswasting.2Onewaytoclassifymasswastingprocessesisonthebasisofthematerialinvolved,suchasrock,debris,earth,ormud.Themannerinwhichthematerialmovesisalsoimportantandisgenerallydescribedasafall,aslide,oraflow.Afalloccurswhenweatheringloosensbouldersfromcliffsorrockfaces,causingtheboulderstobreakawayandfall.Aslidetakesplacewhenevermaterialremainsfairlycoherentandmovesalongawell-definedsurface.Aflowinvolvesthemovementofdebriscontainingalargeamountofwater.3Manymasswastingprocessesaredescribedasslides.Rockslidesoccurwhenacoherentmassofrockbreakslooseandslidesdownaslopeasaunit.Ifthematerialinvolvedismostlyseparatepieces,itiscalledadebrisslide.Slidesareamongthefastestandmostdestructivemassmovements.Usuallyrockslidesoccurinageologicsettingwheretherocklayersareinclined,orwheretherearejointsandfracturesintherockthatareparalleltotheslope.Whensucharockunitisundercutatthebaseoftheslope,itlosessupportandtherockeventuallycollapses.Rainorsnowmeltcantriggerarockslidebywettingtheunderlyingsurfacetothepointthatfrictioncannolongerholdtherockinplace.Thefastesttypeofslideisarockavalanche,inwhichamassofrockliterallyfloatsonairasitmovesdownslope.Thehighspeedofarockavalancheistheresultofairbecomingtrappedandcompressedbeneaththefallingmassofdebris,allowingittomovedowntheslopeasabuoyantsheet.4Mudflowsarerelativelyrapidmasswastingeventsthatinvolvesoilandalargeamountofwater.Becauseoftheirfluidproperties,mudflowsfollowcanyonsandstreamchannels.Mudflowsoftentakeplaceinsemiaridmountainousregionsandontheslopesofsomevolcanoes.Althoughrainstormsinsemiaridregionsareinfrequent,theyaretypicallyheavywhentheyoccur.Whenarainstormorrapidlymeltingsnowcreatesasuddenflood,largequantitiesofsoilandlooserockarewashedintonearbystreamchannelsbecausethereisusuallylittleornovegetationtoanchorthesurfacematerial.Theresultisaflowingmassofwell-mixedmud,soil,rock,andwater.Theconsistencyofthemudflowmaybesimilartothatofwetconcrete,oritmaybeasoupymixturenotmuchthickerthanmuddywater.Thewatercontentinfluencestherateofflowacrossthesurface.Whenamudflowisdense,itmovesmoreslowly,butitcaneasilycarryorpushlargeboulders,trees,andevenhousesalongwithit.5IndrymountainousareassuchassouthernCalifornia,mudflowsareaserioushazardtodevelopmentonandnearcanyonhillsides.Theremovalofnativevegetationbybrushfireshasincreasedtheprobabilityofthesedestructiveevents.Pastmudflowshavecontributedtothebuildupoffan-shapeddepositsatcanyonmouths.Suchfansarerelativelyeasytobuildonandoftenhavescenicviews,somanyhavebecomedesirablesitesforresidentialdevelopment.However,becausemudflowsoccurinfrequently,homeownersareoftenunawareofthepotentialdangerofbuildingonthesiteofapreviousmudflow.6Highlyfluid,fast-flowingmudflowsincorporatefine-grainedsedimentandarecommonaftervolcaniceruptionsthatproducelargevolumesofvolcanicash.Mudflowscontainingvolcanicdebrisarecalledlahars,awordoriginatinginIndonesia,aregionthatexperiencesmanyvolcaniceruptions.Laharsoccurwhenhighlyunstablelayersofashanddebrisbecomesaturatedwithwaterandflowdownsteepvolcanicslopesalongstreamchannels.InthenorthwesternUnitedStates,theeruptionofMountSt.Helensin1980createdseverallaharsthatraceddownthevalleyoftheToutleRiver,alteringthelandscapeinarelativelyshortperiod.56.AllofthefollowingaregivenasfactorsinmasswastingEXCEPT________.A．theangleoftheslopeB．thepresenceofwaterC．theabsenceofplantsD．thetypeofmineral57.Thenameofamasswastingprocessisareflectionof________.A．theareainwhichthemovementoccursB．thematerialthatismovedandthewayitmovesC．therateofmovementrelativetootherprocessesD．themassandvolumeofthematerialinvolved58.Theword“trigger”inparagraph3isclosestinmeaningto________.A．preventB．imitateC．causeD．decrease59.Whydoesarockavalanchemovefasterthanothertypesofrockslides?A．Therockmovesoveralayerofcompressedair.B．Therainfallisheavywhereavalanchesoccur.C．Therockbreaksapartasitmovesdownslope.D．Theangleoftheslopeisalmostvertical.60.Theunderlinedword“that”inparagraph4refersto________.A．resultB．consistencyC．mudflowD．mixture61.Whichsentencebelowbestexpressestheessentialinformationintheunderlinedsentenceinparagraph5?Incorrectchoiceschangethemeaninginimportantwaysorleaveoutessentialinformation.A．Firehasdestroyedmuchoftheoriginalvegetation,somudflowsarenowmorelikely.B．Moredamagetovegetationiscausedbybrushfiresthanbyanyothernaturalevent.C．Itisnecessarytoremovedeadanddamagedvegetationafteramudflowbutnotafterafire.D．Firesoccurfrequentlyinareaswherethevegetationhasbeenclearedfordevelopment.62.Whatcanbeinferredfromparagraph5aboutmudflowsinsomepartsofsouthernCalifornia?A．Mudflowsrarelyoccurmorethanonceinthesamelocation.B．Mudflowscausetheworstdamageinareasthatareheavilyforested.C．Mudflowsoccurmoreoftenthanothernaturaldisasterssuchasfires.D．Mudflowsaresodangerousbecausepeopledonotexpectthemtooccur.63.Whydoestheauthorusetheword“raced”inparagraph6whiledescribingthelaharscausedbytheeruptionofMountSt.Helens?A．ToshowthatlaharsarefasterthanrockavalanchesB．TostateironicallythatlaharsdonotactuallymovequicklyC．ToemphasizethefastspeedoflaharsD．Toexplainwhypeoplecouldnotoutrunthemudflows64.LookatthefoursquaresABCandD,whichindicatewherethefollowingsentencecouldbeaddedtothepassage.Wherewouldthesentencebestfit?Thus,rockslidesoccurmorefrequentlyduringthespring,whenheavyrainsandmeltingsnowaremostprevalent.Manymasswastingprocessesaredescribedasslides.Rockslidesoccurwhenacoherentmassofrockbreakslooseandslidesdownaslopeasaunit.AIfthematerialinvolvedislargelyunconsolidated,itiscalledadebrisslide.Slidesareamongthefastestandmostdestructivemassmovements.Usuallyrockslidesoccurinageologicsettingwheretherocklayersareinclined,orwheretherearejointsandfracturesintherockthatareparalleltotheslope.BWhensucharockunitisundercutatthebaseoftheslope,itlosessupportandtherockeventuallycollapses.Rainorsnowmeltcantriggerarockslidebywettingtheunderlyingsurfacetothepointthatfrictioncannolongerholdtherockinplace.CThefastesttypeofslideisarockavalanche,inwhichamassofrockliterallyfloatsonairasitmovesdownslope.Thehighspeedofarockavalancheistheresultofairbecomingtrappedandcompressedbeneaththefallingmassofdebris,allowingittomovedowntheslopeasabuoyantsheet.DKey:C6 (1)Workingwiththeelderlyisbetterthanmostteenagersrealize.(2)ThissummerIstartedworkingataretirementhomeformycommunityserviceprojectformyhighschool.(3)AtfirstIwasreallyscared.(4)Besideswithmygrandparents,Ihadneverbeenaroundotherolderpeople.(5)IthoughttheymightassumeIwasrudeornotlikemyclothes.(6)Surely,wewouldn’thaveanythingtotalkabout. (7)WhenIarrivedonthefirstday,Ilookedaroundme.(8)Ihadneverseensomanyoldpeopleinoneplacebefore.(9)Butonething:thereweren’tanyhospitalbeds.(10)Twoladieswerewatchingtelevisioninthefrontlobby,anothercomingintosignupforalectureoncomputers.(11)severalwalkedbydiscussingaplay.(12)Anothergentlemanwaswaitingforataxinexttohisluggage. (13)Idiscoveredthatolderpeopleoftenmovetoretirementhomestoliveinacommunitywithpeopleofthesameagewithgoodservices,notbecausetheyaresick.(14)Thesepeoplewerehealthyandactive.(15)Though,IfoundIsharedmoreincommonwiththeresidentsthanIthought.(16)Thereisachessclub.(17)Severaltakeartclasseslikeme.(18)Manyofthemtravel.(19)OnecouplejustreturnedfromGreece.(20)Theretireeswereexcitedtohaveayoungpersonwiththemtoexplaincomputers,talkaboutbooks,ortellthemwhatI’mreadingatschool.(21)Theyjustwanttohavefriendsandtolearnnewthings,likeanybodyelse.65.Inthecontextof