2018年6月英语六级真题及答案(第三套)

./2018年6月英语六级真题及答案〔第三套PartIWriting<30minutes>Directions:Forthispart,youareallowed30minutestowriteanessayontheimportanceofbuildingtrustbetweenbusinessesandconsumers.Youcanciteexamplestoillustrateyourviews.Youshouldwriteatleast150wordsbutnomorethan200words.TheImportanceofBuildingTrustBetweenBusinessesandConsumersToday,inthecontextofthiserafeaturedbyincreasingcommercializationanddigitalization,mutually-trustedrelationsbetweenbusinessesandconsumersappeartobeparticularlyimportant.Asformebusinessesshouldtakealeadingroleinestablishingthetrustrelationship:tobehonestwiththeirconsumers.Firstly,ifabusinesshasadishonestattitudetowarditscustomers,thecustomerswilllackpurchasingconfidenceinitsgoodsorservices,whichwillbringhugeeconomiclosstothebusiness.What'sworse,theadversesideeffectofsuchdishonestycanendangerthebusinessanditisimpossibletorecover.ThecollapseofSanluMilkPowderCompanyisatestamenttothis.Moreover,theincidentofpoisonousmilkhasexerteddevastatingconsequencesonthewholemilkpowdermarket.Besides,becauseoftheproliferationofcounterfeitgoods,moreconsumersloseconfidenceindomesticproducts,andthentheyhavenoalternativebuttoresorttoforeignbrands,whichisonereasonwhycross-borderonlineshoppingisgainingmoreandmorepopularityinChina.Therefore,itishightimeforustostrengthentheimportanceofmaintainingtrustbetweenbusinessesandconsumerstopromotethehealthydevelopmenttofthewholesocialeconomy.PartIIListeningComprehension<30minutes>说明：由于2018年6月六级考试全国共考了两套听力,本套真题听力与前2套容相同,只是选项顺序不同,因此在本套真题中不再重复出现。PartIIIReadingComprehension<40minutes>SectionADirections:Inthissection,thereisapassagewithtenblanks.Youarerequiredtoselectonewordforeachblankfromalistofchoicesgiveninawordbankfollowingthepassage.Readthepassagethroughcarefullybeforemakingyourchoices.Eachchoiceinthebankisidentifiedbyaletter.PleasemarkthecorrespondingletterforeachitemonAnswerSheet2withasinglelinethroughthecenter.Youmaynotuseanyofthewordsinthebankmorethanonce.DidSarahJosephaHalewrite"Mary'sLittleLamb,"theeternalnurseryrhyme<儿歌>aboutagirlnamedMarywithastubbornlamb?Thisisstilldisputed,butit'sclearthatthewoman26forwritingitwasoneofAmerica'smostfascinating27.Inhonorofthepoem'spublicationonMay24,1830,here'smoreaboutthe28author'slife.Halewasn'tjustawriter,shewasalsoa29socialadvocate,andshewasparticularly30withanidealNewEngland,whichsheassociatedwithabundantThanksgivingmealsthatsheclaimedhad"adeepmoralinfluence."Shebegananationwide31tohaveanationalholidaydeclaredthatwouldbringfamiliestogetherwhilecelebratingthe32festivals.In1863,after17yearsofadvocacyincludingletterstofivepresidents,Halegotit.PresidentAbrahamLincoln,duringtheCivilWar,issueda33settingasidethelastThursdayinNovemberfortheholiday.Thetrueauthorshipof"Mary'sLittleLamb"isdisputed.AccordingtotheNewEnglandHistoricalSociety,Halewroteonlypartofthepoem,butclaimedauthorship.Regardlessoftheauthor,itseemsthatthepoemwas34byarealevent.WhenyoungMarySawyerwasfollowedtoschoolbyalambin1816,itcausedsomeproblems.AbystandernamedJohnRoulstonewroteapoemabouttheevent,then,atsomepoint,Haleherselfseemstohavehelpedwriteit.However,ifa1916piecebyhergreat-nieceistobetrusted,Haleclaimedforthe35ofherlifethat"someotherpeoplepretendedthatsomeoneelsewrotethepoem"..A>campaignB>careerC>charactersD>featuresE>fierceF>inspiredG>latterH>obsessedI>proclamationJ>rectifiedK>reputedL>restM>supposedN>traditionalO>versatile.SectionBDirections:Inthissection,youaregoingtoreadapassagewithtenstatementsattachedtoit.Eachstatementcontainsinformationgiveninoneoftheparagraphs.Identifytheparagraphfromwhichtheinformationisderived.Youmaychooseaparagraphmorethanonce.Eachparagraphismarkedwithaletter.AnswerthequestionsbymarkingthecorrespondingletteronAnswerSheet2.GrowPlantsWithoutWaterA>Eversincehumanitybegantofarmourownfood,we’vefacedtheunpredictablerainthatisbothfriendandenemy.Itcomesandgoeswithoutmuchwarning,andafieldoflush<茂盛的>leafygreensoneyearcandryupandblowawaythenext.Foodsecurityandfortunesdependonsufficientrain,andnowheremoresothaninAfrica,where96%offarmlanddependsonraininsteadoftheirrigationcommoninmoredevelopedplaces.Ithasconsequences:SouthAfrica'songoingdrought—theworstinthreedecades—willcostatleastaquarterofitscorncropthisyear.B>BiologistJillFarrantoftheUniversityofCapeTowninSouthAfricasaysthatnaturehasplentyofanswersforpeoplewhowanttogrowcropsinplaceswithunpredictablerainfall.Sheishardatworkfindingawaytotaketraitsfromrarewildplantsthatadapttoextremedryweatherandusetheminfoodcrops.Astheearth'sclimatechangesandrainfallbecomesevenlesspredictableinsomeplaces,thoseanswerswillgrowevenmorevaluable."ThetypeoffarmingI'maimingforisliterallysothatpeoplecansurviveasit'sgoingtogetmoreandmoredry,"Farrantsays.C>Extremeconditionsproduceextremelytoughplants.IntherustyreddesertsofSouthAfrica,steep-sidedrockyhillscalledinselbergsrearupfromtheplainslikethebonesoftheearth.Thehillsareremnantsofanearliergeologicalera,scrapedbareofmostsoilandexposedtotheelements.Yetontheseandsimilarformationsindesertsaroundtheworld,afewfierceplantshaveadaptedtoendureunderever-changingconditions.D>Farrantcallsthemresurrectionplants<复植物>.Duringmonthswithoutwaterunderaharshsun,theywither,shrinkandcontractuntiltheylooklikeapileofdeadgrayleaves.Butrainfallcanrevivetheminamatterofhours.Hertime-lapse<间歇性拍摄的>videosoftherevivalslooklikesomeoneplayingatapeoftheplant'sdeathinreverse.E>Thebigdifferencebetween"drought-tolerant"plantsandthesetoughplants:metabolism.Manydifferentkindsofplantshavedevelopedtacticstoweatherdryspells.Someplantsstorereservesofwatertoseethemthroughadrought;otherssendrootsdeepdowntosubsurfacewatersupplies.Butoncetheseplantsuseuptheirstoredreserveortapouttheundergroundsupply,theyceasegrowingandstarttodie.Theymaybeabletohandleadroughtofsomelength,andmanypeopleusetheterm"droughttolerant"todescribesuchplants,buttheyneveractuallystopneedingtoconsumewater,soFarrantpreferstocallthemdroughtresistant.F>Resurrectionplants,definedasthosecapableofrecoveringfromholdinglessthan0.1gramsofwaterpergramofdrymass,aredifferent.Theylackwater-storingstructures,andtheirexistenceonrockfacespreventsthemfromtappinggroundwater,sotheyhaveinsteaddevelopedtheabilitytochangetheirmetabolism.Whentheydetectanextendeddryperiod,theydiverttheirmetabolisms,producingsugarsandcertainstress-associatedproteinsandothermaterialsintheirtissues.Astheplantdries,theseresourcestakeonfirstthepropertiesofhoney,thenrubber,andfinallyenteraglass-likestatethatis"themoststablestatethattheplantcanmaintain,"Farrantsays.Thatslowstheplant'smetabolismandprotectsitsdried-outtissues.Theplantsalsochangeshape,shrinkingtominimizethesurfaceareathroughwhichtheirremainingwatermightevaporate.Theycanrecoverfrommonthsandyearswithoutwater,dependingonthespecies.G>Whatelsecandothisdry-out-and-revivetrick?Seeds—almostallofthem.Atthestartofhercareer,Farrantstudied"recalcitrantseeds<顽拗性种子>,"suchasavocados,coffeeandlychee.Whiletasty,suchseedsaredelicate—theycannotbudandgrowiftheydryout<asyoumayknowifyou'veevertriedtogrowatreefromanavocadopit>.Intheseedworld,thatmakesthemrare,becausemostseedsfromfloweringplantsarequiterobust.Mostseedscanwaitoutthedry,unwelcomingseasonsuntilconditionsarerightandtheysprout<发芽>.Yetoncetheystartgrowing,suchplantsseemnottoretaintheabilitytohitthepausebuttononmetabolismintheirstemsorleaves.H>AftercompletingherPh.D.onseeds,Farrantbeganinvestigatingwhetheritmightbepossibletoisolatethepropertiesthatmakemostseedssoresilient<迅速恢复活力的>andtransferthemtootherplanttissues.WhatFarrantandothershavefoundoverthepasttwodecadesisthattherearemanygenesinvolvedinresurrectionplants'responsetodryness.Manyofthemarethesamethatregulatehowseedsbecomedryness-tolerantwhilestillattachedtotheirparentplants.Nowtheyaretryingtofigureoutwhatmolecularsignalingprocessesactivatethoseseed-buildinggenesinresurrectionplants—andhowtoreproducethemincrops."Mostgenesareregulatedbyamastersetofgenes,"Farrantsays."We'relookingatgenepromotersandwhatwouldbetheirmasterswitch."I>OnceFarrantandhercolleaguesfeeltheyhaveabettersenseofwhichswitchestothrow,theywillhavetofindthebestwaytodosoinusefulcrops."I'mtryingthreemethodsofbreeding,"Farrantsays:conventional,geneticmodificationandgeneediting.Shesayssheisawarethatplentyofpeopledonotwanttoeatgeneticallymodifiedcrops,butsheispushingaheadwitheveryavailabletooluntiloneworks.Farmersandconsumersalikecanchoosewhetherornottousewhicheverversionprevails："I'mgivingpeopleanoption."J>Farrantandothersintheresurrectionbusinessgottogetherlastyeartodiscussthebestspeciesofresurrectionplanttouseasalabmodel.Justlikemedicalresearchersuseratstotestideasforhumanmedicaltreatments,botanistsuseplantsthatarerelativelyeasytogrowinalaborgreenhousesettingtotesttheirideasforrelatedspecies.TheQueenslandrockvioletisoneofthebeststudiedresurrectionplantssofar,withadraftgenome<基因图谱>publishedlastyearbyaChineseteam.Alsolastyear,Farrantandcolleaguespublishedadetailedmolecularstudyofanothercandidate,Xerophytaviscosa,atough-as-nailSouthAfricanplantwithlily-likeflowers,andshesaysthatagenomeisontheway.Oneorbothofthesemodelswillhelpresearcherstesttheirideas—sofarmostlydoneinthelab—ontestplots.K>Understandingthebasicsciencefirstiskey.Therearegoodreasonswhycropplantsdonotusedrynessdefensesalready.Forinstance,there'sahighenergycostinswitchingfromaregularmetabolismtoanalmost-no-watermetabolism.Itwillalsobenecessarytounderstandwhatsortofyieldfarmersmightexpectandtoestablishtheplant'ssafety."Theyieldisnevergoingtobehigh,"Farrantsays,sotheseplantswillbetargetednotatIowafarmerstryingtosqueezemorecashoutofhigh-yieldfields,butsubsistencefarmerswhoneedhelptosurviveadroughtlikethepresentoneinSouthAfrica."Myvisionisforthesubsistencefarmer,"Farrantsays."I'mtargetingcropsthatareofAfricanvalue."36.Thereareacoupleofplantstoughandadaptableenoughtosurviveonbarerockyhillsandindeserts.37.Farrantistryingtoisolategenesinresurrectionplantsandreproducethemincrops.38.FarmersinSouthAfricaaremoreatthemercyofnature,especiallyinconsistentrainfall.39.Resurrectioncropsaremostlikelytobethechoiceofsubsistencefarmers.40.Eventhoughmanyplantshavedevelopedvarioustacticstocopewithdryweather,theycannotsurviveaprolongeddrought.41.Despiteconsumerresistance,researchersarepushingaheadwithgeneticmodificationofcrops.42.Mostseedscanpullthroughdryspellsandbegingrowingwhenconditionsareripe,butoncethisprocessstarts,itcannotbeheldback.43.Farrantisworkinghardtocultivatefoodcropsthatcansurviveextremedrynessbystudyingthetraitsofrarewildplants.44.Byadjustingtheirmetabolism,resurrectionplantscanrecoverfromanextendedperiodofdrought.45.Resurrectionplantscancomebacktolifeinashorttimeafterarainfall.SectionCDirections:Thereare2passagesinthissection.Eachpassageisfollowedbysomequestionsorunfinishedstatements.ForeachofthemtherearefourchoicesmarkedA>,B>,C>andD>.YoushoulddecideonthebestchoiceandmarkthecorrespondingletteronAnswerSheet2withasinglelinethroughthecenter.PassageOneQuestions46to50arebasedonthefollowingpassage.Humanmemoryisnotoriouslyunreliable.Evenpeoplewiththesharpestfacial-recognitionskillscanonlyremembersomuch.It'stoughtoquantifyhowgoodapersonisatremembering.Noonereallyknowshowmanydifferentfacessomeonecanrecall,forexample,butvariousestimatestendtohoverinthethousands—basedonthenumberofacquaintancesapersonmighthave.Machinesaren'tlimitedthisway.Givetherightcomputeramassivedatabaseoffaces,anditcanprocesswhatitsees—thenrecognizeafaceit'stoldtofind—withremarkablespeedandprecision.Thisskilliswhatsupportstheenormouspromiseoffacial-recognitionsoftwareinthe21stcentury.It'salsowhatmakescontemporarysurveillancesystemssoscary.Thethingis,machinesstillhavelimitationswhenitcomestofacialrecognition.Andscientistsareonlyjustbeginningtounderstandwhatthoseconstraintsare.Tobegintofigureouthowcomputersarestruggling,researchersattheUniversityofWashingtoncreatedamassivedatabaseoffaces—theycallitMegaFace—andtestedavarietyoffacial-recognitionalgorithms<算法>astheyscaledupincomplexity.Theideawastotestthemachinesonadatabasethatincludedupto1milliondifferentimagesofnearly700,000differentpeople—andnotjustalargedatabasefeaturingarelativelysmallnumberofdifferentfaces,moreconsistentwithwhat'sbeenusedinotherresearch.Asthedatabasesgrew,machineaccuracydippedacrosstheboard.Algorithmsthatwereright95%ofthetimewhentheyweredealingwitha13,000-imagedatabase,forexample,wereaccurateabout70%ofthetimewhenconfrontedwith1millionimages.That'sstillprettygood,saysoneoftheresearchers,IraKemelmacher-Shlizerman."Muchbetterthanweexpected,"shesaid.Machinesalsohaddifficultyadjustingforpeoplewholookalotalike—eitherdoppelgangers<长相极相似的人>,whomthemachinewouldhavetroubleidentifyingastwoseparatepeople,orthesamepersonwhoappearedindifferentphotosatdifferentagesorindifferentlighting,whomthemachinewouldincorrectlyviewasseparatepeople."Oncewescaleup,algorithmsmustbesensitivetotinychangesinidentitiesandatthesametimeinvarianttolighting,pose,age,"Kemelmacher-Shlizermansaid.Thetroubleis,formanyoftheresearcherswho'dliketodesignsystemstoaddressthesechallenges,massivedatasetsforexperimentationjustdon'texist—atleast,notinformatsthatareaccessibletoacademicresearchers.TrainingsetsliketheonesGoogleandFacebookhaveareprivate.Therearenopublicdatabasesthatcontainmillionsoffaces.MegaFace'screatorssayit'sthelargestpubliclyavailablefacial-recognitiondatasetoutthere."Anultimatefacerecognitionalgorithmshouldperformwithbillionsofpeopleinadataset,"theresearcherswrote.46.Comparedwithhumanmemory,machinescan________.A>identifyhumanfacesmoreefficientlyB>tellafriendfromamereacquaintanceC>storeanunlimitednumberofhumanfacesD>perceiveimagesinvisibletothehumaneye47.WhydidresearcherscreateMegaFace?A>Toenlargethevolumeofthefacial-recognitiondatabase.B>Toincreasethevarietyoffacial-recognitionsoftware.C>Tounderstandcomputers'problemswithfacialrecognition.D>Toreducethecomplexityoffacial-recognitionalgorithms.48.Whatdoesthepassagesayaboutmachineaccuracy?A>Itfallsshortofresearchers'expectations.B>Itimproveswithaddedcomputingpower.C>Itvariesgreatlywithdifferentalgorithms.D>Itdecreasesasthedatabasesizeincreases.49.Whatissaidtobeashortcoming-offacial-recognitionmachines?A>Theycannoteasilytellapartpeoplewithnear-identicalappearances.B>Theyhavedifficultyidentifyingchangesinfacialexpressions.C>Theyarenotsensitivetominutechangesinpeople'smood.D>Theyhaveproblemsdistinguishingpeopleofthesameage.50.Whatisthedifficultyconfrontingresearchersoffacial-recognitionmachines?A>Nocomputerisyetabletohandlehugedatasetsofhumanfaces.B>Theredonotexistpublicdatabaseswithsufficientfacesamples.C>Therearenoappropriatealgorithmstoprocessthefacesamples.D>Theyhavetroubleconvertingfacedatasetsintotherightformat.PassageTwoQuestions51to55arebasedonthefollowingpassage.There'recurrently21.5millionstudentsinAmerica,andmanywillbefundingtheircollegeonborrowedmoney.Giventhatthere'snowover$1.3trillioninstudentloansonthebooks,it'sprettyclearthatmanystudentsarefarfromsensible.Theaveragestudent'sdebtupongraduationnowapproaches$40,000,andascollegebecomesevermoreexpensive,callstomakeit"free"aremultiplying.EvenHillaryClintonsaysthatwhenitcomestocollege,"Costswon'tbeabarrier."Buttheonlywaycollegecouldbefreeisifthefacultyandstaffdonatedtheirtime,thebuildingsrequirednomaintenance,andcampusesrequirednoutilities.Aslongasit'simpossibletoproducesomethingfromnothing,costsareabsolutelyabarrier.Theactualquestionwedebateiswhoshouldpayforpeopletogotocollege.Iftaxpayersaretobearthecostofforgivingstudentloans,shouldn'ttheyhaveasayinhowtheirmoneyisused?Atleasttaxpayersshouldbeabletodecidewhatstudentswillstudyonthepublicdime.Ifwe'regoingtoforcetaxpayerstofootthebillforcollegedegrees,studentsshouldonlystudythosesubjectsthat'reofgreatestbenefittotaxpayers.Afterall,studentsmakingtheirownchoicesinthisrespectiswhatcausedtheprobleminthefirstplace.Wesimplydon'tneedmorepoetry,genderstudies,orsociologymajors.Howdoweknowwhichsubjectsbenefitsociety?Easy.Averagestartingsalariesgiveaclearindicationofwhattypeoftrainingsocietyneedsitsnewworkerstohave.Certainly,there'rebenefitstoacollegemajorbeyondthejobastudentcanperform.Butifwe'retalkingaboutthebenefitstosociety,theonlythingthatmattersiswhatthemajorenablesthestudenttoproduceforsociety.Andthevalueofwhatthestudentcanproduceisreflectedinthewageemployersarewillingtopaythestudenttoproduceit.Alowwageforelementaryschoolteachers,however,doesn'tmeanelementaryeducationisn'timportant.Itsimplymeansthere'retoomanyelementaryschoolteachersalready.Meanwhile,there'refewwho'rewillingandabletoperformjobsrequiringapetroleumengineeringmajor,sothevalueofonemoreofthosepeopleisveryhigh.Sowecanhavetaxpayerspickupstudents'tuitioninexchangefordictatingwhatthosestudentswillstudy.Orwecanallowstudentsbothtochoosetheirmajorsandpayfortheireducationthemselves.Butintheend,oneoftwothingsistrue:Eitheracollegemajorisworthitscostoritisn't.Ifyes,taxpayerfinancingisn'tneeded.Ifnot,taxpayerfinancingisn'tdesirable.Eitherway,taxpayershavenobusinesspayingforstudents'collegeeducation.51.Whatdoestheauthorthinkofcollegestudentsfundingtheireducationthroughloans?A>Theyonlyexpecttogethugereturns.B>Theyareactinginanirrationalway.C>Theybenefitattaxpayers'expens