英语六级考试真题及答案第套

Documentserialnumber【UU89WT-UU98YT-UU8CB-UUUT-UUT108】英语六级考试真题及 答案 八年级地理上册填图题岩土工程勘察试题省略号的作用及举例应急救援安全知识车间5s试题及答案 第套2018年12月英语六级考试真题及答案(完整版第2套)PartIWriting(30minutes)Directions:Forthispart,youareallowed30minutestowriteanessayonhowtobalancejobresponsibilitiesandpersonalinterests.Youshouldwriteatleast150wordsbutnomorethan200words.________________________________________________________________________________________________________________________________________________________________________________________________________________________HowtoBalanceJobResponsibilitiesandPersonalInterestsIntoday'shighlycompetitiveenvironment,theheavyworkloadmakespeopleoutofbreathandleavesthemnotimefortheirhobbies.Therefore,learningtobalancejobresponsibilitiesandpersonalinterestsisofgreatsignificanceformodernpeople.Herearesomesuggestionswhichcanhelpusachievethebalance.Inthefirstplace,weshouldbeawarethatalthoughworkdutiesareourfirstpriority,itdoesn'tmeanthatwecannotexplorepersonalinterests.Secondly,it'simportanttorealizethatbeneficialactivitiesoffworkhelpusgetrelaxed.Wecantransferourfocusfrombusyworkbyreadinganinterestingbookorlisteningtomusic,therebygettingourintensenervescalmdown.What'smore,findenoughtimetodevelopourhobbiesbyfinishingthetaskontime.Weshouldarrangeourtimereasonablyandcompleteourdailyworkefficiently,whichwillgiveusmorefreedomtoallocatetimetopursuepersonalinterests.Insum,itisabsolutelydo-abletostrikeabalancebetweenfull-timeworkandpersonalhobbiesaslongaswerealizethebenefitofcultivating培养interestsandtheimportanceofreasonabletimearrangement.PartIIListeningComprehension(30minutes)SectionADirections:Inthissection,youwillheartwolongconversations.Attheendofeachconversation,youwillhearfourquestions.Boththeconversationandthequestionswillbespokenonlyonce.Afteryouhearaquestion,youmustchoosethebestanswerfromthefourchoicesmarkedA),B),C)andD).ThenmarkthecorrespondingletteronAnswerSheet1withasinglelinethroughthecentre.Questions1to4arebasedontheconversationyouhavejustheard.1.A)Stopworryingabouthim.B)Keepawayfromthestatue.C)Takeapicture拍照、照相ofhim.D)Patonasmileforthephoto.2.A)Gaininggreatfame名声、名望ontheInternet.B)Publishingacollectionofhisphotos.C)Collectingthebestphotosintheworld.D)Becomingaprofessionalphotographer.3.A)Surfingvariouswebsitesandcollectingphotos.B)Editinghispicturesandpostingthemonline.C)Followingsimilaraccountstocomparenotes.D)Studyingthepicturesinpopularsocialmedia.4.A)Theyarefarfromsatisfactory.B)Theyaremostlytakenbyhermom.C)Theymakeanimpressivealbum.D)Theyrecordherfondmemories.Questions5to8arebasedontheconversationyouhavejustheard.5.A)Ajournalreportingthelatestprogressinphysics.B)Anintroductorycourseofmodemphysics.C)Anoccasionforphysiciststoexchangeideas.D)Aseriesofinterviewswithoutstandingphysicists.6.A)Thefutureofthephysicalworld.B)Theoriginoftheuniverse.C)Sourcesofradiation.D)Particletheory.7.A)Howmattercollideswithanti-matter.B)Whethertheuniversewillturnbarren.C)Whythereexistsanti-matter.D)Whythereisauniverseatall8.A)Matterandanti-matterareoppositesofeachother.B)Anti-matterallowedhumanstocomeintoexistence.C)Theuniverseformedduetoasufficientamountofmatter.D)Anti-matterexistsinveryhigh-temperatureenvironments.SectionBDirections:Inthissection,youwillheartwopassages.Attheendofeachpassage,youwillhearthreeorfourquestions.Boththepassageandthequestionswillbespokenonlyonce.Afteryouhearaquestion,youmustchoosethebestanswerfromthefourchoicesmarkedA,B,CandD.ThenmarkthecorrespondingletteronAnswerSheet1withasinglelinethroughthecentre.Questions9to11arebasedonthepassageyouhavejustheard.9.A)Shefoundherselfspeakingaforeignlanguage.B)Shewokeupspeakingwithadifferentaccent.C)Shefoundsomesymptomsofherillnessgone.D)Shewokeupfindingherselfinanothercountry.10.A)Itisusuallycausedbyastroke中风、行程orbraininjury脑损伤.B)Ithasnotyetfoundanyeffectivetreatment.C)Itleavesthepatientwithadistortedmemory.D)Itoftenhappenstopeoplewithspeechdefects.11.A)British.B)Irish.C)Russian.D)Australian.Questions12to15arebasedonthepassageyouhavejustheard.12.A)Watersports.B)Racinginrivers.C)Storiesaboutwomenswimmers.D)Booksaboutswimming.13.A)ShesucceededinswimmingacrosstheEnglishChannel.B)ShepublishedaguidetoLondon'sbestswimmingspots.C)Shetoldherstoryofadventurestosomeyoungswimmers.D)ShewroteabookaboutthehistoryofswimwearintheUK.14.A)Theylovedvacationingontheseashore.B)Theyhadauniquenotionofmodesty.C)Theywereprohibitedfromswimming.D)Theywerefullydressedwhenswimming.15.A)Shedesignedlotsofappropriateswimwearforwomen.B)Sheoncesuccessfullycompetedagainstmeninswimming.C)ShewasthefirstwomantoswimacrosstheEnglishChannel英吉利海峡.D)Shewasanadvocateofwomen'srighttoswiminpublicpools.SectionCDirections:Inthissection,youwillhearthreerecordingsoflecturesortalksfollowedbythreeorfourquestions.Therecordingswillbeplayedonlyonce.Afteryouhearaquestion,youmustchoosethebestanswerfromthefourchoicesmarkedA,B,CandD.ThenmarkthecorrespondingletteronAnswerSheet1withasinglelinethroughthecentre.Questions16to18arebasedontherecordingyouhavejustheard.16.A)Buildamachinethatcandetect侦查、发现lies谎言.B)Developamagneticbrainscanner.C)Testthecredibilityofcourtevidence.D)Winpeople'scompletetrustinthem.17.A)Theyareoptimisticaboutitspotential.B)Theyarescepticalofitsreliability.C)Theythinkitisbutbusinesspromotion.D)Theycelebrateitwithgreatenthusiasm.18.A)Itisnottobetrustedatall.B)Itdoesnotsoundeconomical.C)Itmayintrudeintopeople'sprivacy.D)Itmayleadtooveruseincourttrials.Questions19to21arebasedontherecordingyouhavejustheard.19.A)Mostofitsresidentsspeakseverallanguages.B)Someofitsindigenouslanguagesaredyingout.C)Eachvillagetherespeaksatotallydifferentlanguage.D)Itslanguageshaveinterestedresearcherstheworldover.20.A)Theyarespreadrandomlyacrosstheworld.B)Somearemoredifficulttolearnthanothers.C)Morearefoundintropical热带的regionsthaninthemild温和zones.D)Theyenrichandimpacteachotherinmorewaysthanone.21.A)Theyuseddifferentmethodstocollectandanalyzedata.B)Theyidentifieddistinctpatternsoflanguagedistribution.C)Theirconclusionsdonotcorrespondtotheiroriginalhypotheses.D)Thereisnoconclusive决定性的account说明、解释forthecauseoflanguagediversity多样性、多元化.Questions22to25arebasedontherecordingyouhavejustheard.22.A)Itsmiddle-class中层阶级、中等的isdisappearing消失.B)Itswealthisrationallydistributed.C)Itspopulationisrapidlygrowing.D)Itscherisheddreamiscomingtrue.23.A)Successwasbutadreamwithoutconscientiouseffort.B)Theycouldrealizetheirdreamsthroughhardwork.C)Afewdollarscouldgoalongway.D)Wealthwassharedbyallcitizens.24.A)Betterworkingconditions.B)Better-payingjobs.C)Highsocialstatus.D)Fullemployment.25.A)Reducetheadministrativecosts.B)Adopteffectivebusinessmodels.C)Hirepart-timeemployeesonly.D)Makeuseofthelatesttechnology.PartIIIReadingComprehension(40minutes)SectionADirections:Inthissection,thereisapassagewithtenblanks.Youarerequiredtoselectonewordforeachblankfromalistofchoicesgiveninawordbankfollowingthepassage.Readthepassagethroughcarefullybeforemakingyourchoices.Eachchoiceinthebankisidentifiedbyaletter.PleasemarkthecorrespondingletterforeachitemonAnswerSheet2withasinglelinethroughthecentre.Youmaynotuseanyofthewordsinthebankmorethanonce.SurfingtheInternetduringclassdoesn'tjuststealfocusfromtheeducator；italsohurtsstudentswho'realreadystrugglingto_F_26_grasp_thematerial.AnewstudyfromMichiganStateUniversity,though,arguesthatallstudents—includinghighachievers—seeadeclineinperformancewhentheybrowsetheInternetduringclassfornon-academicpurposes.TomeasuretheeffectsofInternet-baseddistractionsduringclass,researchers_C_27_evaluated_500studentstakinganintroductorypsychologyclassatMichiganStateUniversity.ResearchersusedACTscoresasameasureofintellectual_A_28_aptitude(天才、天资）_Becausepreviousresearchhasshownthatpeoplewithhighintellectualabilitiesarebetterat_E_29_filtering_outdistractions,researchersbelievedstudentswithhighACTscoreswouldnotshowa_M_30_significant_decreaseinperformanceduetotheiruseofdigitaldevices.ButstudentswhosurfedthewebduringclassdidworseontheirexamsregardlessoftheirACTscores,suggestingthateventheacademicallysmarteststudentsareharmedwhenthey'redistractedinclass.Collegeprofessorsareincreasingly_K_31_raising_alarmbellsabouttheeffectssmartphones,laptops,andtabletshaveonacademicperformance.One2013studyofcollegestudentsfoundthat80%ofstudentsusetheirphonesorlaptopsduringclass,withtheaveragestudentcheckingtheirdigitaldevice11timesina_O_32_typical_class.Aquarterofstudentsreportthattheiruseofdigitaldevicesduringclasscausestheirgradesto_N_33_suffer_.Professorssometimesimplementpoliciesdesignedto_H_34_minimize_students'useofdigitaldevices,andworldwherepeopleareincreasinglysomeinstructorsevenconfiscate(没收）tabletsandphones.Independentontheirphones,though,suchstrategiesoftenfail.Oneinternationalstudyfoundthat84%ofpeoplesaytheycouldn'tgoadaywithouttheirsmartphones.Untilstudentsareableto_L_35_resist抵抗、抗拒_thepullofsocialnetworking,texting,andendlesslysurfingtheweb,theymaycontinuetostraggleintheirclasses.A)aptitudeB)eradicationC)evaluatedD)evaporatedE)filteringF)graspG)legacyH)minimizeI)obscureJ)obsessK)raisingL)resistM)significantN)sufferO)typicalSectionBDirections:Inthissection,youaregoingtoreadapassagewithtenstatementsattachedtoit.Eachstatementcontainsinformationgiveninoneoftheparagraphs.Identifytheparagraphfromwhichtheinformationisderived.Youmaychooseaparagraphmorethanonce.Eachparagraphismarkedwithaletter.AnswerthequestionsbymarkingthecorrespondingletteronAnswerSheet2.APioneeringWomanofScienceRe-Emergesafter300YearsA)MariaSibyllaMerian,likemanyEuropeanwomenofthe17thcentury,stayedbusymanagingahouseholdandrearingchildren.Butontopofthat,Merian,aGerman-bornwomanwholivedintheNetherlands,alsomanagedasuccessfulcareerasanartist,botanist,naturalistandentomologist(昆虫学家).B)"Shewasascientistonthelevelwithalotofpeoplewespendalotoftimetalkingabout,"saidKayEtheridge,abiologistatGettysburgCollegeinPennsylvaniawhohasbeenstudyingthescientifichistoryofMerian'swork."Shedidn'tdoasmuchtochangebiologyasCharlesDarwin,butshewassignificant."C)Atatimewhennaturalhistorywasavaluabletoolfordiscovery,Meriandiscoveredfactsaboutplantsandinsectsthatwerenotpreviouslyknown.Herobservationshelpeddismissthepopularbeliefthatinsectsspontaneouslyemergedfrommud.Theknowledgeshecollectedoverdecadesdidn'tjustsatisfythosecuriousaboutnature,butalsoprovidedvaluableinsightsintomedicineandscience.Shewasthefirsttobringtogetherinsectsandtheirhabitats,includingfoodtheyate,intoasingleecologicalcomposition.D)AfteryearsofpleasingafascinatedaudienceacrossEuropewithbooksofdetaileddescriptionsandlife-sizepaintingsoffamiliarinsects,in1699shesailedwithherdaughternearly5,000milesfromtheNetherlandstoSouthAmericatostudyinsectsinthejunglesofwhatisnowknownasSuriname.Shewas52yearsold.Theresultwashermasterpiece,MetamorphosisInsectorumSurinamensium.E)Inherwork,sherevealedasideofnaturesoexotic,dramaticandvaluabletoEuropeansofthetimethatshereceivedmuchacclaim.Butacenturylater,herfindingscameunderscientificcriticism.Shoddy（粗糙的）reproductionsofherworkalongwithsetbackstowomen'srolesin18th-and19th-centuryEuroperesultedinhereffortsbeinglargelyforgotten."Itwaskindofstunningwhenshesortofdroppedoffintooblivion（遗忘）,"saidDr.Etheridge."Victoriansstartedputtingwomeninabox,andthey'restilltryingtocrawloutofit."F)Today,thepioneeringwomanofthescienceshasre-emerged.Inrecentyears,feminists，historiansandartistshaveallpraisedMerian'stenacity（坚韧）,talentandinspirationalartisticcompositions.AndnowbiologistslikeDr.Etheridgearediggingintothescientifictextsthataccompaniedherart.Threehundredyearsafterherdeath,MerianwillbecelebratedataninternationalsymposiuminAmsterdamthisJune.G)Andlastmonth,MetamorphosisInsectorumSurinamensiumwasrepublished.Itcontains60plates(插图）andoriginaldescriptions,alongwithstoriesaboutMerian'slifeandupdatedscientificdescriptions.BeforewritingMetamorphosis,MerianspentdecadesdocumentingEuropeanplantsandinsectsthatshepublishedinaseriesofbooks.Shebeganinher20s,makingtextless,decorativepaintingsofflowerswithinsects."Thenshegotreallyserious,"Dr.Etheridgesaid.Merianstartedraisinginsectsathome,mostlybutterfliesandcaterpillars."Shewouldsitupallnightuntiltheycameoutofthepupa(桶）soshecoulddrawthem,"shesaid.H)Theresultsofherdecades'worthofcarefulobservationsweredetailedpaintingsanddescriptionsofEuropeaninsects,followedbyunconventionalvisualsandstoriesofinsectsandanimalsfromalandthatmostatthetimecouldonlyimagine.It'spossibleMerianusedamagnifyingglasstocapturethedetailofthesplittonguesofsphinxmoths(斯芬克斯飞蛾）depictedinthepainting.Shewrotethatthetwotonguescombinetoformonetubefordrinkingnectar(花蜜）.Somecriticizedthisdetaillater,sayingtherewasjustonetongue,butMerianwasn'twrong.Shemayhaveobservedtheadultmothjustasitemergedfromitspupa.Forabriefmomentduringthatstageofitslifecycle,thetongueconsistsoftwotinyhalf-tubesbeforemergingintoone.I)Itmaynothavebeenladyliketodepictagiantspiderdevouringahummingbird,butwhenMeriandiditattheturnofthe18thcentury,surprisingly,nobodyobjected.Dr.Etheridgecalleditrevolutionary.Theimage,whichalsocontainednoveldescriptionsofants,fascinatedaEuropeanaudiencethatwasmoreconcernedwiththeexoticstoryunfoldingbeforethemthanthegenderofthepersonwhopaintedit.J)"Allofthesethingsshookuptheirnice,neatlittleview,"Dr.Etheridgesaid.Butlater,peopleoftheVictorianerathoughtdifferently.Herworkhadbeenreproduced,sometimesincorrectly.Afewobservationsweredeemedimpossible."She'dbeencalledasillywomanforsayingthataspidercouldeatabird,"Dr.Etheridgesaid.ButHenryWalterBates,afriendofCharlesDarwin,observeditandputitinbookin1863,provingMerianwascorrect.K)Inthesameplate,Meriandepictedanddescribedleaf-cutterantsforthefirsttime."InAmericatherearelargeantswhichcaneatwholetreesbareasabroomhandleinasinglenight,shewroteinthedescription.Meriannotedhowtheantstooktheleavesbelowgroundtotheiryoung.Andshewouldn'thaveknownthisatthetime,buttheantsusetheleavestofarmfungi(菌类）undergroundtofeedtheirdevelopingbabies.L)Merianwascorrectaboutthegiantbird-eatingspiders,antsbuildingbridgeswiththeirbodiesandotherdetails.Butinthesamedrawing,sheincorrectlylumpedtogetherarmyandleaf-cutterants.Andinsteadofshowingjustthetypicalpairofeggsinahummingbirdnest,shepaintedfour.ShemadeothermistakesinMetamorphosisInsectorumSurinamensiumaswell:noteverycaterpillarandbutterflymatched.M)PerhapsoneexplanationforhermistakesisthatshecutshortherSurinametripaftergettingsick,andcompletedthebookathomeinAmsterdam.Anderrorsarecommonamongsomeofhistory'smost-celebratedscientificminds,too."TheseerrorsnomoreinvalidateMs.Merian'sworkthandowell-knownmisconceptionspublishedbyCharlesDarwinorIsaacNewton,"Dr.Etheridgewroteinapaperthatarguedthattoomanyhavewronglyfocusedonthemistakesofherwork.N)Merian'spaintingsinspiredartistsandecologists.Inan1801drawingfromhisbook,GeneralZoologyAmphibia,GeorgeShaw,anEnglishbotanistandzoologist,creditedMerianfordescribingafrogintheaccountofherSouthAmericanexpedition,andnamedtheyoungtreefrogafterherinhisportrayalofit.Itwouldn'tbefairtogiveMerianallthecredit.Shereceivedassistancenamingplants,makingsketchesandreferencingtheworkofothers.Herdaughtershelpedhercolorherdrawings.O)MerianalsomadenoteofthehelpshereceivedfromthenativesofSuriname,aswellasslavesorservantsthatassistedher.Insomeinstancesshewrotemovingpassagesthatincludedherhelpersindescriptions.Asshewroteinherdescriptionofthepeacockflower,"TheIndians,whoarenottreatedwellbytheirDutchmasters,usetheseedstoaborttheirchildren,sothattheywillnotbecomeslaveslikethemselves.TheblackslavesfromGuineaandAngolahavedemandedtobewelltreated,threateningtorefusetohavechildren.Infact,theysometimestaketheirownlivesbecausetheyaretreatedsobadly,andbecausetheybelievetheywillbebornagain,freeandlivingintheirownland.Theytoldmethisthemselves."P)LondaSchiebinger,aprofessorofthehistoryofscienceatStanfordUniversity,calledthispassageratherastonishing.It'sparticularlystrikingcenturieslaterwhentheseissuesarestillprominentinpublicdiscussionsaboutsocialjusticeandwomen'srights."Shewasaheadofhertime,"Dr.Etheridgesaid.36.MerianwasthefirstscientisttostudyatypeofAmericanant.K37.TheEuropeanaudiencewasmoreinterestedinMerian'sdrawingsthanhergender.I38.Merian'smasterpiececameunderattackacenturyafteritspublication.E39.Merian'smistakesinherdrawingsmaybeattributedtohershortenedstayinSouthAmerica.M40.Merianoftensatupthewholenightthroughtoobserveanddrawinsects.G41.MerianacknowledgedthehelpshegotfromnativesofSouthAmerica.O42.Meriancontributedgreatlytopeople'sbetterunderstandingofmedicineandscience.C43.Merianoccasionallymademistakesinherdrawingsofinsectsandbirds.L44.Now,Merian'sroleasafemaleforerunnerinscienceshasbeenre-established.F45.MerianmadealongvoyagetoSouthAmericatostudyjungleinsectsoverthreecenturiesago.DSectionCDirections:Thereare2passagesinthissection.Eachpassageisfollowedbysomequestionsorunfinishedstatements.ForeachofthemtherearefourchoicesmarkedA),B),C)andD).YoushoulddecideonthebestchoiceandmarkthecorrespondingletteronAnswerSheet2withasinglelinethroughthecentre.PassageOneQuestions46to50arebasedonthefollowingpassage.Whilehumanachievementsinmathematicscontinuetoreachnewlevelsofcomplexity,manyofuswhoaren'tmathematiciansatheart(orengineersbytrade)maystruggletorememberthelasttimeweusedcalculus(微积分）.It'safactnotlostonAmericaneducators,whoamidrisingmathfailureratesaredebatinghowmathcanbettermeetthereal-lifeneedsofstudents.Shouldwechangethewaymathistaughtinschools,oreliminatesomecoursesentirely?AndrewHacker,QueensCollegepoliticalscienceprofessor,thinksthatadvancedalgebraandotherhigher-levelmathshouldbecutfromcurriculainfavorofcourseswithmoreroutineusefulness,likestatistics."Wehearonallsidesthatwe'renotteachingenoughmathematics,andtheChinesearerunningringsaroundus,"Hackersays."I'msuggestingwe'reteachingtoomuchmathematicstotoomanypeople...noteverybodyhastoknowcalculus.Ifyou'regoingtobecomeanaeronautical(航空的）engineer,fine.Butmostofusaren't."Instead,HackerispushingformorecoursesliketheoneheteachesatQueensCollege：Numeracy101.There,hisstudentsof"citizenstatistics"learntoanalyzepublicinformationlikethefederalbudgetandcorporatereports.Suchcourses,Hackerargues,arearemedyforthenumericalilliteracyofadultswhohavecompletedhigh-levelmathlikealgebrabutareunabletocalculatethepriceof,say,acarpetbyarea.Hacker'sargumenthasmetwithoppositionfromothermatheducatorswhosaywhat'sneededistohelpstudentsdevelopabetterrelationshipwithmathearlier,ratherthanteachingthemlessmathaltogether.MariaDroujkovaisafounderofNaturalMath,andhastaughtbasiccalculusconceptsto5-year-olds.ForDroujkova,high-levelmathisimportant,andwhatitcoulduseinAmericanclassroomsisaninjectionofchildlikewonder."Makemathematicsmoreavailable,"Droujkovasays."Redesignitsoit'smoreaccessibletomorekindsofpeople:youngchildren,adultswhoworryaboutit,adultswhomayhavehadbadexperiences."PamelaHarris,alecturerattheUniversityofTexasatAustin,hasasimilarperspective.HarrissaysthatAmericaneducationissufferingfromanepidemicof"fakemath"一anemphasisonrotememorization(死记硬背）offormulasandsteps,ratherthananunderstandingofhowmathcaninfluencethewaysweseetheworld.AndrewHacker,fortherecord,remainsskeptical."I'mgoingtoleaveittothosewhoareinmathematicstoworkoutthewaystomaketheirsubjectinterestingandexcitingsostudentswanttotakeit,"Hackersays."AllthatIaskisthatalternativesbeofferedinsteadofputtingallofusontheroadtocalculus."46.WhatdoestheauthorsayaboutordinaryAmericans?A)Theystruggletosolvemathproblems.B)Theythinkmathisacomplexsubject.C)Theyfindhigh-levelmathoflittleuse.D)Theyworkhardtolearnhigh-levelmath.47.WhatisthegeneralcomplaintaboutAmerica'smatheducationaccordingtoHacker?A)AmericaisnotdoingaswellasChina.B)Mathprofessorsarenotdoingagoodjob.C)Itdoesn'thelpstudentsdeveloptheirliteracy.D)Therehashardlybeenanyinnovationforyears.48.WhatdoesAndrewHacker'sNumeracy101aimtodo?A)Allowstudentstolearnhigh-levelmathstepbystep.B)Enablestudentstomakepracticaluseofbasicmath.C)Layasolidfoundationforadvancedmathstudies.D)Helpstudentstodeveloptheiranalyticalabilities.49.WhatdoesMariaDroujkovasuggestmathteachersdoinclass?A)Makecomplexconceptseasytounderstand.B)Startteachingchildrenmathatanearlyage.C)Helpchildrenworkwonderswithcalculus.D)Trytoarousestudents'curiosityinmath.50.WhatdoesPamelaHarristhinkshouldbethegoalofmatheducation?A)Toenablelearnerstounderstandtheworldbetter.B)Tohelplearnerstotellfakemathfromrealmath.C)TobroadenAmericans'perspectivesonmath.D)Toexe