2018年6月英语六级真题（卷二）

年6月大学英语六级考试真题(第2套）PartIDirections:Forpart,youareallowed30minutesanessaycommentingonimportanceofbuildingtrustbetweenteachersstudents.canexamplesillustrateyourshouldwriteatleast150wordsbutnomorethan200words.PartIIListeningComprehension(30minutes)SectionADirections:Inthissection,youhearlongconversationstheendofeachconversation,youhearfourquestions.Boththeconversationandthequestionsbespokenonlyonce.Afteryouhearaquestion,youmustchoosethebestanswerfromthefourchoicesmarkedandD).ThenmarkthecorrespondingletteronAnswer1asinglelinethroughthecentre.Questions1to4arebasedonconversationyouhaveheard.123.A).Sheadvocatesanimalprotection.Sheisgoingtostartacafechain..A).Theybearalotofsimilarities.B).Shesellsaspecialkindofcoffee.D).Sheistheownerofaspecialcafe.Theyareaprofitablebusinesssector.D).Theyhelpcareofcustomers'pets.C).Theycatertodifferentcustomers..A).givingthemregularcleaningandinjections.selectingbreedsthataretameandpeaceful.placingthematasafedistancefromcustomers.D).briefingcustomersonhowalong4.A).Theywantlearnaboutrabbits.Theybringtheirchildren.D).Theyhercafefavoritereviews.Theytheanimalshercafe.Questions5to8arebasedonconversationyouhaveheard.5.Itcontainstooadditives.D).Itmostlygarbage.can6.A).fancydesign.commercials.D).Peerinfluence.tasteandtexture.7.of.Theyhardlyatevegetables.8Theyseldomhadjunkfood.Theyfavoredchocolate-coatedsweets.D).Theythefoodadvertisedon第1页SectionBDirections:Inthissection,youhearpassages.theendofeachpassage,youhearthreeorfourquestions.Boththepassageandthequestionsbespokenonlyonce.Afteryouhearaquestion,youmustchoosethebestanswerfromthefourchoicesmarkedC)andD).ThenmarkthecorrespondingletteronAnswerSheet1asinglelinethroughthecentre.Questions9to11arebasedonpassageyouhaveheard.91.A).Stretchesoffarmland.TypicalEgyptiananimalD).Ruinsleftbydevastatingfloods.Tombsofancientrulers.0.A).provideshabitatsformoreprimitivetribes.Ithardlyassociatedgreatcivilizations.Ithasnotbeenfullyexploredandexploited.D).gatherswaterfromtropicalrainforests.1.A).carriesaboutoneoftheword'freshwater.Ithasnumeroushumansettlementsalongbanks.ItsecondonlytheMississippiRiverwidth.D).aslongastheandtheYangtzecombined.11Questions12to15arebasedonpassageyouhaveheard.2.A).Livingathefastlaneleadssuccess.arealwaysarushdovariousthings.Thesearchfortranquilityhasbecomeatrend.D).ofusactuallyyearnforaslowandcalm.1113.A).hadtroublebalancingfamilyand4.A).ofThefatiguefromlivingafast-pacedlife.5.A).useenjoyedthevarioussocialevents.D).spentallherleisurewritingbooks.ofherD).Readingabookaboutslowingdown.D).andSectionCDirections:Inthissection,youhearthreerecordingsoflecturesortalksfollowedbythreeorfourquestions.recordingsbeplayedonlyonce.youhearaquestion,youmustchoosethebestanswerfromthefourchoicesmarkedC)andD).ThenmarkthecorrespondingletteronAnswerSheet1asinglelinethroughthecentre.Questions16to18arebasedonrecordingyouhaveheard.1116.A).outaD).Theirinteractionsareharddefine.D).Theirdistinctionsareartificial.Theyposeathreatthelocalecosystem.7.A).Theirclassificationsaremeaningful.Theirdefinitionsarechangeable.8.A).OnlyafewofthemcauseproblemsnativeTheymayturnbenefitthelocalenvironmentofthemcansurvivetheirnewhabitats.第2页D).Only10percentofthemcanbenaturalized.Questions19to21arebasedonrecordingyouhaveheard.19.A).Respecttheirtraditionalculture.Researchtheirspecificdemands.0.A).ShowingthemyourAttendtheirbusinessseminars.D).Adoptthebusinessstrategies.2Givingthemgiftsofgreatvalue.Drinkingalcoholoncertaindaysofamonth.D).Clickingyourfingersloudlytheirpresence.1.2haveastrongsenseofworth.andaQuestions22to25arebasedonrecordingyouhaveheard.22.HeHebyHeofs3.ata222articlesshouldbeshortandinspiring.4.HeHeasaHeHeof5.ofadD).PartIIIReadingComprehensionSectionADirections:Inthissection,thereapassagetenblanks.arerequiredselectonewordforeachblankfromaofchoicesgivenawordbankfollowingthepassage.Readthepassagethroughcarefullybeforemakingyourchoices.Eachchoicethebankidentifiedbyaletter.PleasemarkthecorrespondingletterforeachonAnswerSheet2athroughthecentre.maynotuseanyofthewordsthebankmorethanonce.Questions26to35arebasedonfollowingpassage.)aa,，aaaa第3页of，aofbyabyaAaabyofA).J).G).I).O).N).SectionBDirections:Insection,youaregoingreadapassagetenstatementsattachedEachstatementcontainsinformationgivenoneoftheparagraphs.Identifytheparagraphfromwhichtheinformationderived.maychooseaparagraphmorethanonce.Eachparagraphmarkedaletter.AnswerthequestionsbymarkingthecorrespondingletteronAnswerSheet2.GrowPlantsWithoutWater[Eversincehumanitybegantofarmourownfood,we'vefacedtheunpredictablerainthatisbothfriendandenemy.comesandgoeswithoutmuchwarning,andafieldoflush(茂盛的)leafygreensoneyearcandryupandblowawaythenext.Foodsecurityandfortunesdependonsufficientrain,andnowheremoresothaninAfrica,where96%offarmlanddependsonraininsteadoftheirrigationcommoninmoredevelopedplaces.hasconsequences:SouthAfrica'songoingdrought—theworstinthreedecades—willcostatleastaquarterofitscomcropthisyear.[BiologistJillFarrantoftheUniversityofCapeTowninSouthAfricasaysthatnaturehasplentyofanswersforpeoplewhowanttogrowcropsinplaceswithunpredictablerainfall.Sheishardatworkfindingawaytotaketraitsfromrarewildplantsthatadapttoextremedryweatherandusetheminfoodcrops.Astheearth'sclimatechangesandrainfallbecomesevenlesspredictableinplaces,thoseanswerswillgrowevenmorevaluable."Thetypeoffarmingaimingforisliterallysothatpeoplecansurviveasit'sgoingtoandmoredry,"Farrantsays.Extremeconditionsproduceextremelytoughplants.therustyreddesertsofSouthAfrica,steep-sidedrockyhillscalledinselbergsrearupfromtheplainslikethebonesoftheearth.Thehillsareremnantsofanearliergeologicalera,scrapedbareofmostsoilandexposedtotheelements.Yetontheseandsimilarformationsindesertsaroundtheworld,afewfierceplantshaveadaptedtoendureunderever-changingconditions.[Farrantcallsthemresurrectionplants复苏植物).Duringmonthswithoutwaterunderaharshsun.Theywither,shrinkandcontractuntiltheylooklikeapileofdeadgrayleaves.Butrainfallcanrevivetheminamatterofhours.Hertime-lapse(间歇性拍摄的)videosoftherevivalslooksomeoneplayingatapeoftheplant'sdeathinreverse.第4页[Thebigdifferencebetween"drought-tolerant"plantsandthesetoughplants:metabolism.Manydifferentkindsofplantshavedevelopedtacticstoweatherdryspells.plantsstorereservesofwatertoseethemthroughadrought;otherssendrootsdeepdowntosubsurfacewatersupplies.Butoncetheseplantsuseuptheirstoredreserveortapouttheundergroundsupply,theyceasegrowingandstarttodie.Theymaybeabletohandleadroughtoflength,andpeopleusetheterm"droughttolerant"todescribesuchplants,buttheyneveractuallystopneedingtoconsumewater,soFarrantpreferstocallthemdroughtresistant.[Resurrectionplants,definedasthosecapableofrecoveringfromholdinglessthan0.1gramsofwaterpergramofdrymass,aredifferent.Theylackwater-storingstructures,andtheirexistenceonrockfacespreventsthemfromtappinggroundwater,sotheyhaveinsteaddevelopedtheabilitytochangetheirmetabolism.Whentheydetectanextendeddryperiod,theydiverttheirmetabolisms,producingsugarsandcertainstress-associatedproteinsandothermaterialsintheirtissues.Astheplantdries,theseresourcestakeonfirstthepropertiesofhoney,thenrubber,andfinallyenteraglass-likestatethatis"themoststablestatethattheplantcanmaintain,"FarrantThatslowstheplant'smetabolismandprotectsitsdried-outtissues.Theplantsalsochangeshape,shrinkingtominimizethesurfaceareathroughwhichtheirremainingwatermightevaporate.Theycanrecoverfrommonthsandyearswithoutwater,dependingonthespecies.[Whatelsecandothisdry-out-and-revivetrick?Seeds-almostallofthem.Atthestartofhercareer,Farrantstudied.recalcitrantseeds(执拗性种子),"suchasavocados,coffeeandlychee.Whiletasty,suchseedsaredelicate--theycannotbudandgrowiftheydryout(asmayknowifyou'veevertriedtogrowatreefromanavocadopit).theseedworld,thatmakesthemrare,becausemostseedsfromfloweringplantsarequiterobust.Mostseedscanwaitoutthedry,unwelcomingseasonsuntilconditionsarerightandtheysprout(发芽).Yetoncetheystartgrowing,suchplantsseemnottoretaintheabilitytohitthepausebuttononmetabolismintheirorleaves.[AftercompletingherPh.D.onseeds,Farrantbeganinvestigatingwhetheritmightbepossibletoisolatethepropertiesthatseedssoresilient(迅速恢复活力的)andtransferthemtootherplanttissues.WhatFarrantandothershavefoundoverthepasttwodecadesisthattherearemanygenesinvolvedinresurrectionplants'responsetodryness.Manyofthemarethethatregulatehowseedsdryness-tolerantwhilestillattachedtotheirparentplants.Nowtheyaretryingtofigureoutwhatmolecularsignalingprocessesactivatethoseseed-buildinggenesinresurrectionplants—andhowtoreproducethemincrops."Mostgenesareregulatedbyamastersetofgenes,"Farrantsays."We'relookingatgenepromotersandwhatwouldbetheirmasterswitch."[OnceFarrantandhercolleaguesfeeltheyhaveabettersenseofwhichswitchestothrow,theywillhavetofindthebestwaytodosoinusefulcrops."I'mtryingthreemethodsofbreeding,"Farrant:conventional,geneticmodificationaridgeneediting.Shesayssheisawarethatplentyofpeopledonotwanttoeatgeneticallymodifiedcrops,butsheispushingaheadwitheveryavailabletooluntiloneworks.Farmersandconsumersalikecanchoosewhetherornottousewhicheverversionprevails:"I'mgivingpeopleanoption."[Farrantandothersintheresurrectionbusinesstogetherlastyeartodiscussthebestspeciesofresurrectionplanttouseasalabmodel.Justlikemedicalresearchersuseratstotestideasforhumanmedicaltreatments,botanistsuseplantsthatarerelativelyeasytogrowinalaborgreenhousesettingtotesttheirideasforrelatedspecies.TheQueenslandrockvioletisoneofthebeststudiedresurrectionplantssofar,withadraftgenome(基因图谱)publishedlastyearbyaChineseteam.Alsolastyear,Farrantandcolleaguespublishedadetailedmolecularstudyofanothercandidate,Xerophytaviscosa,atough-as-nailsouthAfricanplantwithlily-likeflowers,andshesaysthatagenomeisontheoneorbothofthesemodelswillhelpresearcherstesttheirideas—sofarmostlydoneinthelab—ontestplots.[Understandingthebasicsciencefirstiskey.Therearegoodreasonswhycropplantsdonotusedrynessdefensesalready.Forinstance,there'sahighenergycostinswitchingfromaregularmetabolismtoanalmost-no-watermetabolism.willalsobenecessarytounderstandwhatsortofyieldfarmersmightexpectandtoestablishtheplant'ssafety."Theyieldisnevergoingtobehigh,"Farrantsays,sotheseplantswillbetargetednotatIowafarmerstryingtosqueezemorecash第5页outofhigh-yieldfields,butsubsistencefarmerswhoneedhelptosurviveadroughtlikethepresentoneinSouthAfrica."Myvisionisforthesubsistencefarmer,"Farrantsays."I'mtargetingcropsthatareofAfricanvalue..3Thereareacoupleofplantstoughandadaptableenoughsurviveonbarerockyhillsanddeserts.Farrantistryingtoisolategenesinresurrectionplantsandreproducethemincrops.FarmersinSouthAfricaaremoreatthemercyofnature,especiallyinconsistentrainfall.Resurrectioncropsaremostlikelytobethechoiceofsubsistencefarmers.333Eventhoughmanyplantshavedevelopedvarioustacticstocopewithdryweather,theycannotsurviveaprolongeddrought.Despiteconsumerresistance,researchersarepushingaheadwithgeneticmodificationofcrops.Mostseedscanpullthroughdryspellsandbegingrowingwhenconditionsareripe,butoncethisprocessstarts,itcannotbeheldback.Farrantisworkinghardtocultivatefoodcropsthatcallsurviveextremedrynessbystudyingthetraitsofrarewildplants.Byadjustingtheirmetabolism,resurrectionplantscanrecoverfromanextendedperiodofdrought.Resurrectionplantscanbacktolifeinashorttimeafterarainfall.SectionCDirections：Thereare2passagesinthissection.Eachpassageisfollowedbysomequestionsorunfinishedstatements.ForofthemtherearefourchoicesmarkedA),B),C)andYoushoulddecideonthebestchoiceandmarkthecorrespondingletteronAnswerSheet2withasinglelinethroughthecentrepassageoneQuestions4650arebasedonthefollowingpassage.Humanmemoryisnotoriouslyunreliable.Evenpeoplewiththesharpestfacial-recognitionskillsonlyremembersomuch.toughtoquantifyhowapersonisremembering.onereallyknowshowmanydifferentfacessomeonerecall,forexample,butvariousestimatestendtohoverinthethousands-basedonthenumberofacquaintancesapersonmighthave.Machinesaren'tlimitedthisGivetherightcomputeramassivedatabaseoffaces,anditprocesswhatitsees-thenrecognizeait'stoldtofind-withremarkablespeedandprecision.Thisskilliswhatsupportstheenormouspromiseoffacial-recognitionsoftwareinthe2lstIt'salsowhatmakescontemporarysurveillancesystemssoThethingis,machinesstillhavelimitationswhenitcomestofacialrecognition.AndscientistsonlyjustbeginningtounderstandwhatthoseconstraintsTobegintofigureouthowcomputersstruggling,researcherstheUniversityofWashingtoncreatedamassivedatabaseoffaces-theycallitMegaFace-andtestedavarietyoffacial-recognitionalgorithms(算法)theyscaledupincomplexity.Theideatotestthemachinesonadatabasethatincludedupto1milliondifferentimagesofnearly700,000differentpeople-andnotjustalargedatabasefeaturingarelativelysmallnumberofdifferentfaces,moreconsistentwithwhat'susedinotherresearch.thedatabasesmachineaccuracydippedacrosstheboard.Algorithmsthat5%ofthetimewhentheydealingwitha13,000-imagedatabase,forexample,accurate9about70%ofthetimewhenconfrontedwith1millionimages.That'sstillprettyoneoftheresearchers,Kemelmacher-Shlizerman."Muchbetterthanexpected,said.Machinesalsohaddifficultyadjustingforpeoplewholookalotalike-eitherdoppelgangers(长相极相似的人),whomthemachinewouldhavetroubleidentifyingtwoseparatepeople,orthesamepersonwhoappearedindifferentphotosdifferentorindifferentlighting,whomthe第6页machinewouldincorrectlyviewseparatepeople.Oncescaleup,algorithmsmustbesensitivetotinychangesinidentitiesandthesame"timeinvarianttolighting,pose,"Kemelmacher-Shlizermansaid.Thetroubleis,formanyoftheresearchersliketosystemstoaddressthesechallenges,massivedatasetsforexperimentationjustexist--atleast,notinformatsthataccessibletoacademicresearchers.TrainingsetsliketheonesGoogleandFacebookhaveprivate.Therenopublicdatabasesthatcontainmillionsoffaces.MegaFace'screatorssayit'sthelargestpubliclyavailablefacial-recognitiondatasetoutthere.“ultimaterecognitionalgorithmshouldperformwithbillionsofpeopleinadataset,”theresearcherswrote.Comparedwithhumanmachines.A)identifyhumanfacesmoreefficientlyB)tellafriendfromamereacquaintanceC)storeunlimitednumberofhumanfacesperceiveimagesinvisibletothehumanWhydidresearcherscreateMegaFace?Toenlargethevolumeofthefacial-recognitiondatabaseToincreasethevarietyoffacial-recognitionsoftwareC)Tounderstandcomputers'problemswithfacialrecognitionToreducethecomplexityoffacial-recognitionalgorithms48.Whatdoesthepassagesayaboutmachineaccuracy?fallsshortofresearchers'expectations.improveswithaddedcomputingpower.C)variesgreatlywithdifferentalgorithms.decreasesthedatabasesizeincreases.45Whatissaidtobeashortcomingoffacial-recognitionmachines?Theycannoteasilytellapartpeoplewithnear-identicalappearances.TheyhavedifficultyidentifyingchangesinfacialexpressionsTheynotsensitivetominutechangesinpeople'smoodTheyhaveproblemsdistinguishingpeopleofthesameageWhatisthedifficultyconfrontingresearchersoffacial-recognitionmachines?computerisabletohandledatasetsofhumanfacesTheredonotexistpublicdatabaseswithsufficientfacesamplerC)TherenoappropriatealgorithmstoprocessthefacesamplesTheyhavetroubleconvertingfacedatasetsintotherightformat.PassageTwoQuestions5155arebasedonthefollowingpassage.There’currently21.5millionstudentsinAmerica,andmanywillbefundingtheircollegeonborrowedGiventhatthere'snowover$1.3trillioninstudentloansonthebooks,it'sprettythatmanystudentsfromsensible.Theaveragestudent'sdebtupongraduationnow第7页approaches$40,000,andcollegebecomesmoreexpensive,callstomakeit"free"multiplying.EvenHillaryClintonthatwhenitcomestocollege,"Costswon'tbeabarrier."theonlycollegecouldbeisifthefacultyandstaffdonatedtheirtime,thebuildingsrequirednomaintenance,andcampusesrequirednoutilities.longit'simpossibletoproducesomethingfromnothingcostsabsolutelyabarrier.Theactualquestiondebateiswhoshouldpayforpeopletotocollege.taxpayerstothecostofforgivingstudentloans,shouldn'ttheyhaveasayinhowtheirmoneyisused?leasttaxpayersshouldbeabletodecidewhatstudentswillstudyonthepublicdime.goingtotaxpayerstofootthebillforcollegedegrees,studentsshouldonlystudythosesubjects’ofgreatestbenefittotaxpayers.Afterall,studentsmakingtheirownchoicesinthisrespectiswhatcausedtheprobleminthefirstplace.Wesimplydon'tmoregenderstudies,orsociologymajors.HowdoknowwhichsubjectsbenefitAveragestartingsalariesaindicationofwhatoftrainingsocietyneedsitsnewworkerstohave.Certainly,there'rebenefitstoacollegemajorbeyondthejobastudentperform.iftalkingaboutthebenefitstosociety,theonlythingthatmattersiswhatthemajorenablesthestudenttoproduceforsociety.Andthevalueofwhatthestudentproduceisreflectedinthewageemployerswillingtopaythestudenttoprod