大学英语四级考试模拟试题四及答案详解

大学英语四级考试模拟试题四及答案详解

PartIWriting(30minutes)

Directions:Forthispart,youareallowed30minutestowriteanAddressofWelcome.Youshould

writeatleast120wordsfollowingtheoutlinegivenbelow.

学生会邀请了来自某大学的李教授作一个关于计算机人工智能的演讲。作为主持人，你在演

讲前作一个开场白。请写一份简明的欢迎词。（1.简明介绍演讲者；2.计算机人工智能的作

用；3.表示欢迎等）

AddressofWelcome

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11.A)Neitherofthemhasafavorableopinionoftheservice.

B)Thewomanishavingaterribletimeservingintherestaurant.

C)Bothagreethatitistimefortherestauranttofiresomestaff.

D)Themanthinkstherestaurantisallright,butthewomandoesn't.

12.A)Heeatstoomuchwhenheplayschess.

B)Hewon'tjointhechessclub.

C)Chessishisfavoritegame.

D)Hedoesn'tenjoychessasmuchasheusedto.

13.A)Annshouldshutthedoor.

B)Annshouldbequieter.

C)Annshouldn'thavestayedatthelibrarysolong.

D)Annshouldn'thavereturnedhome.

14.A)Shehasanothermeetingallday.

B)Shefeelsthegradeisallright.

C)Shethinksitwouldbewrongtochangethegrade.

D)Shecanmeetwiththestudentthatafternoon.

15.A)Theclothesdon'tlookcleantohim.

B)Hedoesn'tintendtogettheclothes.

C)Thewomancanpickoutherownclothes.

D)Thewomanshouldstopstaringathisclothes.

16.A)Shewon'tbeabletocome.

B)She'snotgoingtograduate.

C)Shehasaweektodothework.

D)She'llvisithersisterinaweek.

17.A)Shethinksahairdryer.

B)Shewantstoknowwhat'smakingallthenoise.

C)Sheisn'tsurehowpracticaltheman'sgiftis.

D)Shecan'thearanythingwhenthehairdryerison.

18.A)Shehasn'treadthepassage.

B)Shedoesn'tunderstanditeither.

C)Shecannotreaditindarkness.

D)Shesuggeststhatthemanreadit.

Questions19to22arebasedontheconversationyouhavejustheard.

19A)Shereceivedanemergencycallthepreviousday.

B)Shehasneverbeentothecitybefore.

C)Shewouldgotheretospendtheweekendwithhersister.

D)Shewasinvitedtoattendhersister'swedding.

20.A)Inlessthananhour.C)At11:13.

B)Inaminute.D)Atnoon.

21.A)Someonetotalkwith.

B)Interestingbookstoread.

C)Somethingtoeatanddrink.

D)Puzzlesandcrosswordgames.

22.A)Thirteenpennies.C)Apound.

B)Fiftypennies.D)Halfprice.

Questions23to25arebasedontheconversationyouhavejustheard.

23.A)It'sratherexpensive.

B)It'stoosmallfortheman.

C)Ithasplentyoflight.

D)Itdoesn'thavemanyclosets.

24.A)Eachtenantisgivenaparkingplace.

B)It'sdifficulttofindaparkingplace.

C)Thetenanthastopaytopark.

D)Thetenantcanuseanyspaceintheparkingarea.

25.A)He'sunimpressedbywhatthewomantoldhim.

B)Hedoubtshecanaffordit.

C)Hedoesn'tthinkit'ssuitableforhim.

D)He'senthusiasticaboutit.

SectionB:

Directions:Inthissection,youwillhear3shortpassages.Attheendofeachpassage,youwill

hearsomequestions.Boththepassageandthequestionswillbespokenonlyonce.Afteryouhear

aquestion,youmustchoosethebestanswerfromthefourchoicesmarkedA),B),C)andD).

ThenmarkthecorrespondingletteronAnswerSheet2withasinglelinethroughthecentre.

PassageOne

Questions26to28arebasedonthepassageyouhavejustheard.

26.A)Theircostisverylow.

B)Theycanbeusedinmanycountries.

C)Thewillnotpollutetheenvironment.

D)Theyneedlittleexperimentation.

27.A)Itgathersheatfromthesun.

B)Itpushesaturbineinadam.

C)Itcauseswindstoturnawindmill.

D)Itwarmsupthelandalongthecoast.

28.A)SlowingdowntheEarth'srotation.

B)Harmingthecoastline.

C)Changingthewavepattern.

D)Pollutingthewater.

PassageTwo

Questions29to31arebasedonthepassageyouhavejustheard.

29.A)Astudyofaresearchcorporation.

B)Oneoflife'sessential.

C)Thereasonswhypeopledon'tlikebreakfast.

D)Breakfastandhumanhealth.

30.A)Takingnobreakfastdoesgoodtoone'shealth.

B)Takingnobreakfastdoesnoharmtoone'shealth.

C)Scientificevidenceisnotenough.

D)Eatinglittleinthemorningisgoodforus.

31.A)Anyonewithoutbreakfastdoesimprovehisperformance.

B)Nothavingbreakfastimproveone'sperformance.

C)Havingbreakfastimproveone'sperformance.

D)Performanceisnotrelatedtowhetherhavingbreakfastornot.

PassageThree

Questions32to35arebasedonthepassageyouhavejustheard.

32.A)HowRayKrocmademoneyforthebrothers.

B)Howtostartourownrestaurant.

C)ArestaurantinCaliforniain1948.

D)HowtheMcDonald'sbusinessstartedandgrew.

33.A)Theywantedcustomerstopayless.

B)Customerswouldgettheirmealsquickly.

C)Theycoulduseplasticplates.

D)Theydidn'tneedwaitersandwaitresses.

34.A)Thefoodwasdeliciousandhealthful.

B)Itwasquickandcheap.

C)Itwasfamousinthecity.

D)Itwasdifferentandnew.

35.A)Theycouldmakealotoffriendsthere.

B)Theylikedthebrothers.

C)Theyenjoyedthefood,thetoysandthegamesthere.

D)Theirparentsaskedthemtogothere.

SectionC:

Directions:Inthissection,youwillhearapassagethreetimes.Whenthepassageisreadforthe

firsttime,youshouldlistencarefullyforitsgeneralidea.Whenthepassageisreadforthesecond

time,youarerequiredtofillintheblanksnumberedfrom36to43withtheexactwordsyouhave

justheard.Forblanksnumberedfrom44to46youarerequiredtofillinthemissinginformation.

Fortheseblanks,youcaneitherusetheexactwordsyouhavejustheardorwritedownthemain

pointsinyourownwords.Finally,whenthepassageisreadforthethirdtime,youshouldcheck

whatyouhavewritten.

Britainischangingmorerapidlythaneverbeforeinherlonghistory.Insomerespectsthenew

Britishsociety(36)____________generalworldtrends.Inotherrespectsithaskeptitsown(37)

_________flavor.Britishsocietyisevolving,thatistosay,developingandsuitingitselftorapidly

changingconditions.Evolutionratherthanrevolutionorviolentchangeisaspecial(38)

_________oftheBritishwayoflife.

ThisisshowninonewaybyhowtheBritishpeoplevoteat(39)___________.TheConservative

andLaborPartieshavecontrolledthe(40)__________sceneforthelastfiftyyears,buttoday

neitherpartycananylongerbesurefromwhichclassorincomegroupits(41)_________will

come.NotlongagoyouwouldhaveexpectedtheworkingclassesalwaystovotefortheLabor

Party.Theword"labor"means"hardwork"-(42)___________hardworkwiththehands.The

LaborPartyisthepartywhichissupposedto(43)__________the"workingman".Youwould

alsohaveexpectedtheupperandmiddleclassestovotefortheConservativeParty.Theword

conservativemeans"keepingthingsastheyare".TheConservativeParty(44)

_______________________________________________________________________________.

InsomerespectstraditionalBritish"classdistinctions"arebecominglessclear,andyoucanbe

lesssurehowpeoplewillvote.Manymembersofthemiddleclasssupportsocialreform.Many

ordinaryworkingpeople(45)_______________________________________________________

__________________________________.Buttheolddivisionsbetweentheclassesremain.

ManyConservativesfearthatthesovereigntyofParliamentisbeingthreatenedbytheTrade

Unions.ManyworkersareafraidthattheConservativebossesaretryingtokeeptheirwagesdown.

Butclassfeelingshavenotreachedapersonallevelyet.(46)____________________

_________________________________________________________________.

PartIIReadingComprehension(SkimmingandScanning)(15minutes)

Directions:Inthispart,youwillhave15minutestogooverthepassagequicklyandanswerthe

questionsonAnswersheet1.

Forquestions1-7,mark

Y(forYES)ifthestatementagreeswiththeinformationgiveninthepassage;

N(forNO)ifthestatementcontradictstheinformationgiveninthepassage;

NG(forNOTGIVEN)iftheinformationisnotgiveninthepassage.

Forquestions8-10,completethesentenceswiththeinformationgiveninthepassage.

NewProposalsonYouthEmployment

TheunemploymentrateinJapancontinuestohoverataroundthe5%level,butthenumberof

unemployedyouthsisexceptionallyhighcomparedtootheragegroups.Thefluidsituationis

graduallytakingrootinsociety,withanincreasingnumberofyouthsmakingalivingas"freeters"

(asyoungjob-hoppersarecalledinJapan)orleavingandchangingjobsevenaftertheyfind

employment.Thisyouthemploymentproblemisessentiallyaproductofmanycompanies'

guardedstance(姿态)onemploymentandthenarrowingofemploymentopportunitiesforthose

seekingtoworkasregularemployees.

Todealwiththeyouthemploymentproblem,thegovernmentandrelevantinstitutionshave

alreadypresentedvariousproposalsforspecificpolicies,suchastostrengthenpoliciesthatcan

turneconomicrecoveryintoavigorousincreaseoflabordemand;whileexpandingjobopenings

forregularemployees,alsotopromoteequaltreatmentofnon-regularemployeesandsecure

opportunitiesforthemtobecomeregularemployeessothattheworkingstylesofnon-regular

employeesarenotdisadvantaged;fromtheearlieststageaspossible,systematicallytoprovidejob

preparatoryeducationwithalong-rangeoutlookoncareerdevelopment.Someofthesepolicies

areactuallybeingimplemented,buttheyarenotnecessarilyproducingadequateresults.Forthis

reason,thefollowingthreenewmeasuresshouldbeconsideredinadditiontoothermeasures

beingdeliberated.

Reformofemploymentandrecruitmentpractices

?Itisimportantthathighschoolgraduatesaregivenasmanyopportunitiesaspossibletoselectan

occupation.Whilecompletelyabolishingtheone-person-one-companysystemononehand,onthe

otherhand,employmentandcareerguidanceshouldbeginwhenstudentsenterhighschoolso

theyarewellabletoselectanoccupationontheirownjudgment.

?Also,theyearaftergraduationshouldberegardedasaperiodofjointfollow-upbyschoolsand

employmentagencies.Especiallyinregardtounemployedgraduatesandfreeters,eachparty

shouldassessthesituationandsupporttheemploymentofthoseyoungpeople.

?Withrespecttocollegestudents,internshipopportunities,careercounseling,andotherguidance

schemesshouldbeimplementedsoonaftertheyentercollegetoeventuallyenablethemtomake

independentcareerdecisions.

?Companiesshouldgivedueconsiderationtotheacademicaccomplishmentofstudentswhen

screeningjobapplicants,asthatistheprimaryfunctionofstudents.Universitiesshoulddrawupon

France'sbaccalaureatesystem,forexample,andintroduceasystemofuniversitygraduation

examinationorcollegeacademiccertificationtest.

?Finally,asameasuretoexpandemploymentopportunities,companiesshouldamendtheir

traditionalpracticeofrecruitingonlyprospectivenewgraduatesandopentheirdoorstothosewho

havealreadygraduated.

Enhancingcareereducationandtheroleofindustries

?Careereducationaimingtocultivateworkvaluesshouldbeaconsecutive(连续的)program

providedoveranampleamountoftimebeginningintheprimary,juniorhigh,andhighschool

compulsoryeducationstage.

?Inadditiontoteachingstudentsaboutthesignificanceofworkingandaboutoccupationsin

general,careereducationshouldalsoincludeacourseon"workanddailyliving"asa

comprehensivecourseaimingtopreparestudentstobecomeworkingmembersofsociety.The

courseshoulddealwithabroadrangeoftopicsrelatingtotheworkconcept,suchasrightsand

obligationsstipulatedinlaborlaws,aswellaswiththemechanicsofthepensionsystemandother

socialsecurityinstitutionsandwithsuchimmediateissuesastheenvironmentandenergy.Sucha

coursewouldhelpyouthstoselecttheirownlifestyles,includinghowtoachieveagoodbalance

betweenworkandprivatelife.

?Theindustrialcommunityshouldformorganizationsofcompanies(suchasNPOs)toaddress

careereducationfromacross-cuttingperspectiveandactivelyengageinactivitiestosupportthe

developmentofhumanresourcesforthenextgeneration.Forexample,theyareexpectedto

developandprovideeducationalprogramsbasedontheiruniquetechnologyandknow-how,send

personneltoschools,andofferfundsandequipment.

?InregionalareasinJapan,activitiestorevitalizeregionalindustriesandpromotenewindustries

shouldbelinkedtomodelprojectsthatincorporateregionalcharacteristicsandaimtofosterand

retainyoungpeopleasfutureleadersoftheregion.Forexample,localgovernmentscouldutilize

the500orsoyoungworkers'centersthroughoutJapanasthebasesofsuchprojectswiththe

cooperationofregionalbusinessesandschools.

Proposalofa"careerpassport"

?The"careerpassport"wouldfunctionasarecordofone'scareerandasacertificationforthe

utilizationofvarioussupportmeasures.Itwouldbeissuedtoallyouthsovertheageof18and

wouldbeapassporttocontinuoussupportvaliduptotheageof30to35.

?Thepassportwouldcontainarecordofjobchanges,part-timeexperiences,studies,certifications

andself-developmentefforts,inadditiontoaccomplishmentsachievedthroughparticipationin

volunteerandNPOactivities.Inthisrespect,itwouldtaketheformofanelectroniccardtoallow

theinputandaccumulationofinformationthroughadigitalformatthatcanbeaccessedbythe

individualwhenevernecessary.

?Thepassportwouldenableyoungworkerstoreceivecareercounselingregularlyorasnecessary

atjobcafesthatarebeingnewlyestablishedoratthemorethan500youngworker'scenters

throughoutJapan.Theywouldalsohavetheopportunitytocheckandevaluatetheirowncareers,

includingpart-timeexperiences,andeffectivelyutilizevarioussupportprogramsforemployment,

capacitydevelopmentandotherareasnecessaryfordevelopingtheircareers.

?Inadditiontotheabove,avocationalscholarshipsystemshouldbecreatedtoprovidefinancial

supportforeducationalcoursesandschoolexpensestoallyoungpeoplewhohavegraduated

school-includingtheunemployed,freeters,anddisplacedworkers-sothattheymayvoluntarily

preparethemselvesforajobordeveloptheirworkingcapacities.

1.Theyouthfrequentjobchangesresultinmanycompanies'guardedstanceontheiremployment.

2.Toofferdifferentjobopportunitiestobothyouthregularandnon-regularemployees.

3.Employmentandcareerguidanceshouldbepartofhighschoolcurriculum.

4.Companiesshouldrevisetheirpoliciestorecruitbothnewandoldgraduates.

5.Theschoolcourseshoulddealwithabroadrangeoftopicsrelatingtotheworkconceptsuchas

jobhuntingandhopping.

6.Thereareabout500youthcentersinsomelocalareas.

7.Thecareerpassportcontainspart-timeexperiences,studies,certificateandself-development

exceptjob-hopping.

8.Collegeeducationshouldenablestudentstomake____________________.

9.Companiesshouldprovideeducationalprogramandsendpersonneltoschoolsandoffer

____________________.

10.Inordertoprovideyoungpeoplewithfinancialsupport,weshouldcreate________________

________.

PartIIIListeningComprehension(35minutes)

SectionA

Directions:Inthissection,youwillhear8shortconversationsand2longconversations.Atthe

endofeachconversation,oneormorequestionswillbeaskedaboutwhatwassaid.Boththe

conversationandthequestionswillbespokenonlyonce.Aftereachsectiontherewillbeapause.

Duringthepause,youmustreadthefourchoicesmarkedA),B),C)andD),anddecidewhichis

thebestanswer.ThenmarkthecorrespondingletteronAnswerSheet2withasinglelinethrough

thecentre.

PartIVReadingComprehension(ReadinginDepth)(25minutes)

SectionA

Directions:Inthissection,thereisapassagewithtenblanks.Youarerequestedtoselectoneword

foreachblankfromalistofchoicesgiveninawordbankfollowingthepassage.Readthepassage

throughcarefullybeforemakingyourchoices.Eachchoiceinthebankisidentifiedbyaletter.

PleasemarkthecorrespondingletterforeachitemonAnswerSheet2withasinglelinethrough

thecentre.Youmaynotuseanyofthewordsinthebankmorethanonce.

Questions47to56arebasedonthefollowingpassage.

Oncetheworldembracedtheautomobile,thedaysofdependingonhorses,bicycles,ferries,and

trainsquicklyslippedintothepast.Peoplewere__47__withthespeedoftheautomobilebutthey

werealsoenjoyingthepersonalfreedomthattheautomobilegavethem.Owningacargavepeople

thefreedomtogoanyplacearoad__48__.Thisallowedpeopletotravelatanytimeandattheir

own__49__.Thisindependencegavethecarapopularedgeoverbusesandtrains.

Thepopularityoftheautomobilemadeitthe__50__ofthetransportationsystem.Theautomobile

changedourliveswhenitcreatedagiantindustrythatofferedmoreandmorejobs.The

automobilemadeitpossibleforpeopletoliveinareas__51__fromtheirworkplace.Thiscaused

citiestogrowandmadesuburbanlivingmoreconvenient.Ofcourse,withmoreplacestogo,

more__52__roadshadtobebuilt.Theautomobilecauseda__53__effect.Jobsincreased,

industriesgrew,newindustriesdeveloped,andcitiesappeared.Todaytheautomobileindustry

continuestooffermany__54__.Jobsareplentifulinthisindustryandimprovementscontinueto

bemadetotheautomobilewithnewtechnologies.

Wehavecomealongwayfromthatfirst__55__carriagebecauseofthecooperativeeffortsof

manypeopleinthelastcentury.Itwillbeinterestingtoseewhatthefutureholdsforthe

automobile.Wehavealreadyseensignsoftheuseofsolarenergyinthisarea.Aslongasmanhas

abrain,thefutureoftheautomobileis__56__.

A)backboneI)opportunities

B)infiniteJ)snowball

C)furtherK)definite

D)backgroundL)developed

E)ledM)farther

F)enjoyedN)impressed

G)horselessO)pace

H)developing

SectionB

Directions:Thereare2passagesinthissection.Eachpassageisfollowedbysomequestionsor

unfinishedstatements.ForeachofthemtherearefourchoicesmarkedA),B),C)andD).You

shoulddecideonthebestchoiceandmarkthecorrespondingletteronAnswerSheet2witha

singlelinethroughthecentre.

PassageOne

Questions57to61arebasedonthefollowingpassage.

Ifyouwanttoteachyourchildrenhowtosaysorry,youmustbegoodatsayingityourself,

especiallytoyourownchildren.Buthowyousayitcanbequitetricky.

Ifyousaytoyourchildren"I'msorryIgotangrywithyou,but…"whatf"oclalnowsthat"but

rendertheapologyineffective:"Ihadabadday"or"yournoisewasgivingmeaheadache"leaves

thepersonwhohasbeeninjuredfeelingthatheshouldbeapologizingforhisbadbehaviorin

expectinganapology.

Anothermethodbywhichpeopleappeartoapologizewithoutactuallydoingsoistosay"I'm

sorryyou'reupset";thissuggeststhatyouaresomehowatfaultforallowingyourselftogetupset

bywhattheotherpersonhasdone.

Thenthereisthegeneral,allcoveringapology,whichavoidsthenecessityofidentifyingaspecific

actthatwasparticularlyhurtfulorinsulting,andwhichthepersonwhoisapologizingshould

promisenevertodoagain.Saying"I'muselessasaparent"doesnotcommitapersontoany

specificimprovement.

Thesepseudo-apologiesareusedbypeoplewhobelievesayingsorryshowsweakness.Parents

whowishtoteachtheirchildrentoapologizeshouldseeitasasignofstrength,andthereforenot

resorttothesepseudo-apologies.

Butevenwhenpresentedwithexamplesofgenuinecontrition,childrenstillneedhelptobecome

awareofthecomplexitiesofsayingsorry.Athree-year-oldmightneedhelpinunderstandingthat

otherchildrenfeelpainjustashedoes,andthathittingaplaymateovertheheadwithaheavytoy

requiresanapology.Asix-year-oldmightneedremindingthatspoilingotherchildren's

expectationscanrequireanapology.A12-year-oldmightneedtobeshownthatraidingthebiscuit

tinwithoutaskingpermissionisacceptable,butthatborrowingaparent'sclotheswithout

permissionisnot.

57.Ifamotheradds"but"toanapology,_______.

A)shedoesn'tfeelthatsheshouldhaveapologized

B)shedoesnotrealizethatthechildhasbeenhurt

C)thechildmayfindtheapologyeasiertoaccept

D)thechildmayfeelthatheowesheranapology

58.Accordingtotheauthor,saying"I'msorryyou'reupset"mostprobablymeans"_______".

A)Youhavegoodreasontogetupset

B)I'mawareyou'reupset,butI'mnottoblame

C)Iapologizeforhurtingyourfeelings

D)I'matfaultformakingyouupset

59.Itisnotadvisabletousethegeneral,all-coveringapologybecause_______.

A)itgetsoneintothehabitofmakingemptypromises

B)itmaymaketheotherpersonfeelguilty

C)itisvagueandineffective

D)itishurtfulandinsulting

60.Welearnfromthelastparagraphthatinteachingchildrentosaysorry_______.

A)thecomplexitiesinvolvedshouldbeignored

B)theiragesshouldbetakenintoaccount

C)parentsneedtosetthemagoodexample

D)parentsshouldbepatientandtolerant

61.Itcanbeinferredfromthepassagethatapologizingproperlyis_______.

A)asocialissuecallingforimmediateattention

B)notnecessaryamongfamilymembers

C)asignofsocialprogress

D)notassimpleasitseems

PassageTwo

Questions62to66arebasedonthefollowingpassage.

Leaddeposits,whichaccumulatedinsoilandsnowduringthe1960'sand70's,wereprimarilythe

resultofleadedgasolineemissionsoriginatingintheUnitedStates.Inthetwentyyearsthatthe

CleanAirActhasmandatedunleadedgasuseintheUnitedStates,theleadaccumulation

world-widehasdecreasedsignificantly.

AstudypublishedrecentlyinthejournalNatureshowsthatair-borneleadedgasemissionsfrom

theUnitedStatesweretheleadingcontributortothehighconcentrationofleadinthesnowin

Greenland.ThenewstudyisaresultofthecontinuedresearchledbyDr.CharlesBoutron,an

expertontheimpactofheavymetalsontheenvironmentattheNationalCenterforScientific

ResearchinFrance.AstudybyDr.Boutronpublishedin1991showedthatleadlevelsinarctic北(

极的)snowweredeclining.

Inhisnewstudy,Dr.Boutronfoundtheratiosofthedifferentformsofleadintheleadedgasoline

usedintheUnitedStatesweredifferentfromtheratiosofEuropean,AsianandCanadiangasoline

andthusenabledscientiststodifferentiate(分区)theleadsources.Thedominantleadratiofound

inGreenlandsnowmatchedthatfoundingasolinefromtheUnitedStates.

InastudypublishedinthejournalAmbio,scientistsfoundthatleadlevelsinsoilinthe

North-easternUnitedStateshaddecreasedmarkedlysincetheintroductionofunleadedgasoline.

Manyscientistshadbelievedthattheleadwouldstayinsoilandsnowforalongerperiod.

TheauthorsoftheAmbiostudyexaminedsamplesoftheupperlayersofsoiltakenfromthesame

sitesof30forestfloorsinNewEngland,NewYorkandPennsylvaniain1980andin1990.

Theforestenvironmentprocessedandredistributedtheleadfasterthanthescientistshadexpected.

Scientistssaybothstudiesdemonstratethatcertainpartsoftheecosystem(生态系统)respond

rapidlytoreductionsinatmosphericpollution,butthatthesefindingsshouldnotbeusedasa

licensetopollute.

62.ThestudypublishedinthejournalNatureindicatesthat________.

A)theCleanAirActhasnotproducedthedesiredresults

B)leaddepositsinarcticsnowareontheincrease

C)leadwillstayinsoilandsnowlongerthanexpected

D)theUSisthemajorsourceofleadpollutioninarcticsnow

63.LeadaccumulationworldwidedecreasedsignificantlyaftertheuseofunleadedgasintheUS

________.

A)wasdiscouragedC)wasprohibitedbylaw

B)wasenforcedbylawD)wasintroduced

64.HowdidscientistsdiscoverthesourceofleadpollutioninGreenland?

A)ByanalyzingthedatapublishedinjournalslikeNatureandAmbio.

B)Byobservingtheleadaccumulationsindifferentpartsofthearcticarea.

C)BystudyingthechemicalelementsofsoilandsnowinNortheasternAmerica.

D)Bycomparingthechemicalcompositionsofleadedgasolineusedinvariouscountries.

65.Theauthorsof