2023年考研考博-考博英语-西安交通大学考试历年高频考点真题荟萃带答案

2023年考研考博-考博英语-西安交通大学考试历年高频考点真题荟萃带答案第1卷一.综合题(共25题)1.翻译题1.根据牛顿的发现,白光是所有可见光叠加而成的。这就是加色概念的典型例子。例如去掉蓝色色调,白光就会变为黄色,还有其他例子等等。然而当把颜料的所有颜色混合,我们会得到黑色,这就是典型的减色理论,黑色代表所有颜色都存在。加色是透射光的领域的概念,减色是色素、染料和化学品的领域的概念。2.但是我们对创新的追求究竟是为了实现什么呢?创新就是一种重要的新产品或者新程序,或者是一项制度,能够在实际生活中大范围的应用,对经济和社会有着革命性的意义,就是以更低成本实现更高的工作效益。遗憾的是我们现在几乎把一切事情都用创新来形容,因为不是所有创新都能给社会财富的増长和生活的改善提供一个长久的平台。3.睡眠问题研究者发现,总的来说,大多数人都是随着年龄的增加,睡眠问题却越来越少,上了年纪的人反而对失眠有更好的承受力。睡眠模式的大多改变都发生在20岁到60岁之间。那些经历着睡眠问题的人,应该去看医生才好。因为他们经历的问题也许是某种生病的迹象,也许是一些药物的副作用。ChooseONLYONEtextformthefollowingandtranslateitintoEnglish.WriteyourtranslationontheAnswerSheetprovidedifmorethanONEtranslationappearsontheAnswerSheet,onlythefirstortheindicatedonewouldbescored

2.单选题Thechieffoodseateninacountrydependslargelyon（）bestinitsclimateandsoil.问题1选项A.allwhatitgrowsB.whatgrowsC.whichgrowsD.whatdoesitgrow3.单选题OrangejuiceandbeefformpartofthedietofmanypeopleinMexicoandothercountriesoftheAmericas.Butthetracesofantibioticsandfungicidestheycancontainposeriskstohumanhealth,andauthoritiesintheregionhavebeguntoaddresstheproblem.InJanuary2012,theUSFoodandDrugAdministration(FDA)announcedabanon‘extralabel'orunapprovedusesofcephalosporinantimicrobialdrugsincattle,swine,chickensandturkeysasofApril2012.Asaresult,MexicowillbeforcedtograduallyeliminatetheuseofthisclassofantimicrobialdrugsinordertocontinuetoexportproductstomarketsliketheUnitedStates,becausecattleinMexico,whichhasatotalherdof25millionheadaccordingtotheministryofagriculture,receivelargedosesofantibioticslikepenicillin,tetracyclineandcephalosporinstopreventbacterialinfections.Mexico'sministryofagriculturehasactuallyamanualforgoodlivestockpracticesregardingraisingbeefinfeedlots,whichrecommendsonlyusingregisteredmedications,notusingapprovedcombinationsofmedicines,andusingnarrowspectrumantimicrobialstotreataspecificdiseasewheneverpossible.Inaddition,regulationsfortheNationalAnimalIdentificationSystemarependingapproval.Thesystem,whichcoverscattle,sheep,goats,horses,swineandbees,willprovideforcompletetraceabilityofanimalsandproducts.Anumberofscientificstudieshavefoundtracesofdrugsinanimalproducts.OneexampleisthestudycarriedoutinthewesternMexicanstateofJalisco,thecountry'sleadingmilkproducer“EvaluationofthepresenceofantibioticandchemotherapyresiduesinmilkinJalisco,Mexico”,publishedin2009intheAnimalHealthJournal.ItcanbeconcludedthatthereisaproblemofcontaminationwithantimicrobialsinthemilkconsumedinJalisco,inviolationofthecountry'sregulations,saysthestudybyfiveresearchersattheUniversityCenteronBiologicalandAgriculturalSciencesoftheUniversityofGuadalajara.Ofthe264samplesanalyzed,26(9.8percent)hadresiduesofantimicrobialdrugs,and77percentofthesamplesthattestedpositivefortraceshadatleastonesulfonamide.SinceMexicoproducesmorethan10billionlitersofmilkayear,accordingtoministryofagriculturefigures,“Mexicoshouldshifttoapolicyofnon-chemicalcontrols,”saidthechiefresearcher.TheInternationalProgrammeonChemicalSafety,acooperativeprogramme,oftheWorldHealthOrganization,InternationalLaborOrganizationandUNEnvironmentProgrammesaysthefungicidecanremaininthesoilforuptothreeyears.HowevertheseissuesarenotaddressedbytheNationalStrategyforSustainableProductionandConsumptionthattheMexicangovernmentisdrafting.1.Whichofthefollowingcanbeastatementofthemainideaofthispassage?2.TheNationalAnimalIdentificationSystem（）.3.Therehasbeenevidencethat（）.4.“Mexicoshouldshifttoapolicyofnon-chemicalcontrols”means（）.5.Fungicidescallremainsinthesoilforupto（）.6.Thetopicofthispassageis（）.7.Thetoneofthispassagecanbedescribedas（）.8.Theword“addressed”(Line1,lastparagraph)canbebestreplacedby（）

.问题1选项A.Orangejuiceandbeefformpart&thedietofmanyMexicanpeople.B.Mexicoexportscattle,swine,chickensandturkeystotheUnitedStateseveryyear.C.Mexicoshouldkeeptracesofantibioticsoutoffood.D.MexicanMinistryofAgriculturefailstocontrolfoodproducts问题2选项A.hasbeenapprovedrecentlybytheMinistryofAgricultureofMexicoB.cantraceanimalsandtheproductsfromthemC.standardizesanimalraisingintheworldD.hasbeendraftedbytheexpertsoftheagriculturalministryexperts问题3选项A.MexicananimalproductshavetracesofdrugsusedinthecourseoftheirgrowthB.heUnitedStatesannouncedabanonanimalproductsfromMexicoC.contaminationwithantimicrobialshasbeenwidelyfoundinMexicanfoodproductsD.77%OfMexicananimalproductshavetracesofchemicals问题4选项A.MexicoshouldprohibittheUseofchemicalsinanimalsB.MexicoshouldadoptapolicyofnotcontrollingchemicalusesC.Mexicangovernmentcontrolledchemicaluseinthepast,butnotinthefutureD.Mexicangovernmentshouldchangethepolicyofnotcontrollingchemicals问题5选项A.threedaysB.threeweeksC.threemonthsD.threeyears问题6选项A.MexicandietarytraditionsB.MexicanagriculturalproduceC.contaminationofMexicananimalfoodproductsD.Mexicansustainableproduction问题7选项A.affectiveB.criticalC.objectiveD.subjective问题8选项A.dealtwithB.saidC.talkedD.mentioned4.单选题In1885OwenWister(1850-1938)recordedthat“itwon’tbeacenturybeforethewestissimplythetrueAmerica,withthought,type,andlifeofitsown”andhewanted“tobethehandthatonce,forall,chronicledandlaidbarethevirtuesandtheicesofthisextraordinaryphaseofAmericansocialprogress.”Heneverbecamethatself-envisionedTolstoioftheoldWest,butin1902TheVirginianwaspublished.Itwoninstantsuccessandsky-rocketeditsauthortofame.Itisstillthemostpopular“western”noveleverpublishedandthemasterdesignforthefictionoftheWildWest.TheVirginianestablishedaliteraryform,aformulapopularlyknownas“horseopera”,whoseconventions,cliches,andvalueshavereappearedinnovelsandshortstories,inmoviesandtelevisionserials,eversince.Theromanticcowboyistheheroandgentleman,oneofthose“goodmeninthehumblerwalksoflife”,whoseemsthroughshams,defendsjusticeandalady’shonor,shootsitoutwiththevillainandconquersevil.BecauseofTheVirginian,Wistercreatedacharacterwhoistheoriginaltypeforthewesternfolkhero.HerepresentstheembodimentofcertainAmericanideals—amanwhoisequaltoalloccasionswhoshowsindependenceofaction,amanwhokeepshiswordwhoisabroad-gaugefellowlivingamongnarrow-gaugefold”.ButtheliterarydeviceandcowboycodewhichWisterestablisheddictatedthattheheromustkilltheheadman.Thisnecessityforsanctioningmurderandromanticizingofthecowboyasagentlemanprohibited.TheVirginianandthegenreitcreatedfrombecomingseriousfiction,orevenanauthenticproductofthewesternexperience.Insteadofachievinghisambition,therefore,WistergaveusasortofAmericanfolkepic,thecowboystory.1.OwenWisterbelieved（）.2.Stylistically,TheVirginianisnotedforthefactthatit（）.3.ThepopularitywhichwasaccordedTheVirginianindicatesthatWister（）.4.Theauthorofthearticlebelievesthat（）.问题1选项A.thewayoflifeinthewestin1885wasapassingphaseB.thecowboyin1885symbolizedthetypicalAmericanmodeC.thewestwouldbealwaysisolatedfromtherestofthecountrybyitsmoralcodeD.noneofthese问题2选项A.waswrittenaccordingtoapre-establishedformulaB.establishedtheformulaknownas“horseopera”C.followedtheliteraryconventionsoftheday.D.abandonedAmericanconventionsinfavorofforeignones问题3选项A.hadwrittenanaccountofthecowboywhichappealedtoAmericanaspirationsB.gaveusanauthenticaccountofthewesternexperienceC.becametheAmericanTolstoiD.realizedhisstatedambition问题4选项A.TheVirginiandidnotdeservethesuccessitwonB.WisterwasahackC.WistermadeadefinitecontributiontoAmericanliteratureD.cowboystoriesshouldbeconsideredseriousfiction5.填空题Familiescomeinmanyshapesandsizes.Whodoyouincludewhenyoutalkabout“yourfamily”？Yourfamilymightbethefamilyyouwerebornintoorthefamilyyouhavecreatedwithyourpartner.Youmightincludejustyourpartner,orfamiliesoneorbothofyoubringfrompreviousrelationships.Youmightlivewithpeopleyouregardasfamilyeventhoughtheyarenotbloodrelatives.Thepossibilitiesaremany.Familiesmaybebasedondifferentkindsofadultrelationshipsbutthethingtheyhaveincommonisthattheyprovideasenseofbelonging.Theygiveidentityandprovidesupportandsecurity.Yourfamilyismadeupofthepeopleyoucareaboutandthepeoplewhocareaboutyou.Youmightalsowanttoincludeanyclosefriendsthatyouhaveafamily-likerelationshipwith,peopleyoucanrelyonandtrust.Theserelationshipsmightbethepeopleyoulooktowhenyourextendedfamilyliveelsewhereorarenotavailabletogiveyouactivesupport.Havingaconceptofyourfamilythatgoesbeyondmum,dadandthekidsisalsoimportantwhenadultrelationshipsbreakup.Whenparentsseparate,childrenoftenfindsecurityinwideranddifferentfamilyconnections.Oftenthesetakeindifferentgenerationsandwidercirclesoffriends.Theword“family”canmeandifferentthingstodifferentpeople.Butnomatterhowourfamiliesaremadeup.Mostsharesomecommonvalues.It'sworththinkingaboutwhattheseare.Whenwestartthinkingvaluesoffamilies,it'slikelythatmostfamilieswillcomeupwithafairlycommonsetofprinciples.Forinstance,mostwouldsaythesupportoneanother,trustoneanother,careforeachotherwhenthingsgettough,sharetheirresourcesandmakesureeveryoneinthefamilyissafe.It'simportanttotalkaboutwhatbindsustogetherbecausethisishowchildrenlearnabouthowtotreatothers.Whattheylearnathomeaboutrespectingandcaringforothers,andtakingresponsibility,feedsintotheirrelationshipsatschool,onthesportsfield,atworkandeventually,intotheirownfamiliesasadults.Sometimesparentshaven'thadtheopportunitytothinkaboutthesesortsofthings.Ortheyhavebeenraisedinfamiliesthatwerenotsafe,wheretheywereabused,hurtornotrespected.However,it'spossibletobreakthiscycle.Wecanchoosetobuildfamiliesthataredifferentfromtheoneswegrewupin.Forinstance,therearelotsofthingswecandotomakeourfamiliesworkwell.Wecanlearnhowtocommunicatesothatourmessagesandfeelingsareunderstoodandweunderstandhowotherpeoplearefeelingandwhattheyaretryingtotellus.Wecanalsolearnhowtoresolveconflictinsafewaysthatstrengthenourrelationshipsandreinforceourvalues.Conflictisaninevitable,naturalandhealthypartoffamilylife.Nomatterhowclosewearetosomeonewewillfinddifferences,andsomeofthesewillbeirritatingtous.Butonceweunderstandtheotherperson'spointofviewourrelationshipwiththemwillimprove.Andwecanlearnhowtomakedecisionsandplanaheadasafamily.Regardlessofourownbackground,itispossibleforustodecidewhatwewantasafamilyandtakestepstowardsmakingithappen.Whenthepeopleyoulovemakedecisionsyoudon'tlike,doyouchoosetobelovingorwouldyouratherberight?Youhavehighexpectationsofthepeopleyoucareabout.Youknowtheyarecapableofdoingwell.Youonlywantwhat'sbestforthem.Maybeyoualsowantwhat'sbestfromthemtoo.That'sabitdifferent.It'saboutwhatyougetratherthanwhattheyget.Lookingatitlikethatyourmotivesmightnotseemsonoble,andyourpartner,oryourteenager,oryourfriendmightbequicktopointthatoutasawayofdiscountingyourview.Youmightsaytoyourteenager“Ireallyhopeyou'llgotoUniversity.Itwasastruggleformetogetthere.Itookyearsandhadtodoitparttime.Iwantyoutohavethechancetoenjoyitbeforeyougettieddownwithkidsandmortgages.I'mworriedthatyou'llwanttodoitlater,whenI'mnolongerinapositiontohelpyoufinancially.Willitchangewhattheydo?Probablynot.They'llmaketheirownchoices,completewithpredictedmistakesandunexpectedtriumphs.It'snottheirjobtolivethelifeyouwantedtohave,oreventheoneyouwanttogivethem.Willtheybefuriouswithyouforinterfering,fortellingthemwhattodo,anddoubtingtheirabilitytocompetentlymanagetheirownlife?Probablynot.Allyou'vedoneistellthemwhatyouwant,andwhattheirdecisionmeansforyou.Whenyoutellyourownstoryandletpeopleknowhowyoufeel,yourmotivations,yourhopesandyourgoodintentionsaremuchmoreapparent.You'rebeingopenaboutwhatyouhopetogainoravoid.Itbecomespossibleforsomeonetoappreciateyourconcerneveniftheychooseapathyoudon'tfavor.Theydon'thavetodefendthemselvesbecauseyou'renotcriticizingthem.Theydon'thavetobeattackingbecauseyouarebeingloving.Theydon'thavetoresistyou,becauseyouaren'ttryingtocontrolthem.Concentrateontalkingaboutyou,yourexperience,yourhopesandfears.Youcan't“fix”someoneelse.Youcanaskabouttheirthoughtsandworriesanddreamsandgetamuchfullerpictureofwhatthey'redoing.Youcanchoosetobelovingandtakegoodcareoftherelationshipyoushare.Thatwayiftheyeverdoneedadviceorencouragementorsupportyou'llbesomeonetheywanttoturnto.Beinglovingwon'tmakesomeonedancetoyourtune,butitwillhelptokeepaconnectionbetweenyou.1.Theconceptofone'sfamilycangobeyond（）.2.Inafamily,memberssupportoneanother,trustoneanother,careforeachotherwhenthingsgettough,andmakesureeveryoneinthefamilyissafe.Allofthiscanbesummarizeas（）.3.Whatvalueschildrenlearnathomecanfeedsinto（）atschool,onthesportsfield,atwork,andeventuallytheirownfamiliesasadults.4.Peoplecanbuildbetterfamiliesthatare（）theonestheygrewupinandwhichtheyfeelwereabusive.5.Whenfamilymembersyoulovemakedecisionsonedoesn'tlike,youhavetobalancebetweenchoosingtobelovingand（）.6.单选题Thehelicopterisanincrediblyversatilemachine.Itcanfly,straightupordown,hoverlikeafly,andgoforwards,backwards,orsideways.Itthereforeneedsnolong,preparedrunwaylikeanormalairplanedoes.Itcanoperatefromaflatroofinthecityorfromaclearinginthejunglewithequalease.However,helicoptersarenowherenearasfastasnormalfixed-wingairplanesandhaveatopspeedofonlyabout200milesanhour.Thehelicopterhasoftenbeencalledthe'flyingwindmill'becauseofthelong,rotatingblades,orrotor,ontopofitsbody.Thismainrotorservesasbothpropellerandwingstoprovidethethrusttodrivethehelicopteralongandthelifttoraiseitofftheground.Therotorbladeshavethesameaero-foilshapesasairplanewingsandpropellerstogeneratetherequiredliftandthrust.Whenthemainrotorrotates,thebodyofthehelicopterlendstospinbyreactionintheoppositedirection.Tocounteractthiseffect,asmallrotorismountedsidewaysonthetail.Thethrustproducedbythistailrotorinnormalflightjustbalancestheturningtendencyofthehelicopterbodywhichthereforeremainssteady.Boththemainandthetailrotorsaredrivenbythehelicopterenginethroughthesamegearbox.Anotherwayofmaintainingstabilityintheairistohavetwinmainrotorswhicheachrotateinoppositedirections.Then,the"spinning"tendencyofonecancelsthatoftheother.Movementofthehelicopterinadirection-forwards,backwards,sideways,upordown-isachievedsimplybyvaryingthepitchoftherotorblades.Thepitchistheangleatwhichthebladesslicethroughor'bite'theair.Toflystraightupwardsallthebladesaresetatthesamesharppitch.Inthispositiontheyachievemaximumlift.Todescend,thepitchofthebladesisreducedsothattheliftisinsufficienttosupportthehelicopter'sweight.Thepilotadjuststhepitchforupordownmovementbymovingthecollective-pitchstick.Thisisalsolinkedtotheenginethrottlessothatmorepowerisappliedasthepitchincreases.Thisistoovercomethegreaterairresistancewiththesharperpitch.Conversely,theengineisthrottledbackwhenthepitchisreducedfordescentbecausethereislessairresistance.Toflyforwards,thepitchoftherotorbladesisvariedastheyrotate.Forforwardmotion,thepitchismadeleastatthefrontandgraduallyincreasedastheblademovesbackwards.Thishastheeffectofsweepingtheairbackwards,andthereforepushingthehelicopterforwards.Thesamegoesforanyhorizontalmovement——thepitchismadeleastinthedesireddirectionoftravel.Thecyclic-pitchstickcontrolsthepitchoftherotorforhorizontalflight.1.Fromthefirstparagraphwecaninferthat（）.2.What'sthebasicfunctionofthemainrotorofahelicopter?3.Themovementofthehelicopterinanydirectioniscontrolledby（）.4.Toflyforwards,ahelicopterhasto（）.5.Theword"descend"inline4ofparagraph4canbebestreplacedby（）.6.Thephrase"Thisposition"inline4ofparagraph4refersto（）.7.Whatisthemostappropriatetitleforthispassage?问题1选项A.nothingisperfectB.generallyspeaking,helicoptersarebetterthanotherairplanesC.fixed-wingairplaneshaveatopspeedofabout200milesperhourD.helicoptersarenotatallversatile问题2选项A.Tocounteractthespinningofahelicopter.B.Tomaintainstabilityintheair.C.Torotateinoppositedirection.D.Toproducetheforcetodriveitalongandthelifttoraiseitofftheground.问题3选项A.asmallrotorB.itstailC.varyingthepitchoftherotorbladesD.counteractingmaximumlift问题4选项A.supportthehelicopter'sweightB.sweeptheairbackwardsandpushthehelicopterforwardsC.belinkedtotheenginethrottleD.slicethroughtheair问题5选项A.settleB.comeC.godownD.decrease问题6选项A."Toflystraightupwards"B."thesamesharppitch"C."Thepitch"D.''achievemaximumlift”问题7选项A.TheHelicopterB.ThePitchC.RotatingBladesD.TheflyingHelicopter7.单选题（）itshotsunandbeautifulbeaches,Hawaiiisafineplacetoliveinortovisit.问题1选项A.AsB.ForC.FromD.With8.单选题Therearethreeimportantcausesofinflation.Thefirstandmostimportantcausemaybeexcessivegovernmentspending.Forexample,inorderto（1）awaror（2）socialprograms,thegovernmentmayspendmoremoneythanithasreceivedthroughtaxesandotherrevenue,thuscreatingadeficit.Inorderto（3）thisdeficit,theTreasuryDepartmentcansimply（4）themoneysupplybyissuingmorepapermoneytoreturnthedebtsofthegovernment.Thisincreaseinthemoneysupplywillcausethevalueofthedollarto（5）decrease.Thesecondcauseofinflationwilloccurwhenthemoneysupplyincreasesfasterthanthesupplyofgoods.Ifpeoplehavemoremoney,theywillrunouttobuypopulargoodsliketelevisionandcomputers,forexample,andashortagewillbetheresult,industrywillthenproducemore,athigherprices,to（6）thedemand,（7）ifpeoplethinkthatthepricesofpopulargoodsaregoingup,theywillbuyandevenborrowmoneyathigh（8）ratestopayforthem.Finally,iflaborunionsdemandthatworkers'wages（9）tosuitthehighcostofliving,industrywillmeetthisdemandandaddothercostsofproductiononthe（10）.Ofthesethreecauses,excessivegovernmentspendingmaybethemostimportant.问题1选项A.payB.financeC.rouseD.provide问题2选项A.carryoffB.carryawayC.carryoutD.carry,over问题3选项A.accomplishB.offsetC.compensateD.achieve问题4选项A.expandB.extendC.expendD.offend问题5选项A.excessivelyB.automaticallyC.approximatelyD.appropriately问题6选项A.supplyB.implyC.occupyD.meet问题7选项A.OtherwiseB.HenceC.HoweverD.Moreover问题8选项A.interestsB.interestedC.interestingD.interest问题9选项A.shouldincreaseB.beincreasedC.areincreasedD.willbeincreased问题10选项A.employerB.managerC.employeeD.consumer9.单选题Onecommon-sensereason（）childrenlearntospeakisthattheyimitatethosearoundthem.问题1选项A.whichB.whatC.thatD.ofwhich10.单选题AccordingtoaUnitedStateslawpassedin1986,statesparticipatingindaylightsavingtime（）advancetheirclocksonehouronthelastSundayinApril.问题1选项A.conceptuallyB.systematicallyC.simultaneouslyD.purposefully11.单选题Deathcomesquicklyinthemountains.Eachwinterholidaymakersarecaughtunawaresastheyhappilyskiawayfromthefixedruns,littlerealizingthatasmallavalanchecansendthemcrashinginabone-breakingfalldowntheslopeandleavethemburiedundertonsofcrispwhitesnow.Therearelotsoftheoriesabouthowtoavoiddisasterwhenhitbyanavalanche.Practiceisnormallylesscheerful.ThesnowintheSalzburgofAustriawherearecentdisastertookplacewastypicalavalanchematerial.ForseveraldaysbeforetheincidentIhadskiedlocally.Earlywintersnowwaswearingthinandcoveredwithice.Ontopofthatnew,warmerflakesweregentlyfallingtoproduceadangerouscarpet.Totheskierwhoenjoysunmarkedslopesitistemptingstuff,deepnewpowersnowonahardbase—theskiingthatdreamsaremadeofandsometimesnightmares.Snowfallsinsectionslikeacake.Differentsectionshavedifferentdensitiesbecauseofthetemperaturesatthetimeofthefallandintheweeksafterwards.Problemscomewhenanyparticularsectionistoothickandnotstickingtothesectionbeneath.ThesnowofthepastfewweekshadbeenfallinginratherhighertemperaturesthanthoseofDecemberandearlyJanuary.Theresultoftheseconditionsisthatevenaslightincreaseinthetemperaturessendsathinstreamofwaterbetweenthenewsnowandtheold.Thenthenewsnowsimplyslidesoffthemountain.Suchslidesarenotunexpected.Localcitizensknowtheslopeswhichtendtoavalancheandtheweatherinwhichsuchslidesarelikely.Trapsaresettocatchthesnoworpreventitslipping;bombsareplacedandexplodedfromtimetotimetosetoffsmallavalanchesbeforeabigonehastimetobuildup;andaboveall,skiersarewarnednottoskiindangerareas.Inspiteofthis,avalancheshappeninunexpectedareasand,ofcourse,skiersignorethewarnings.Theonecomforttorecreationalskiers,however,isthatavalancheincidentsonthemarkedskislopesarequiterare.Noskiresortwantstheimageofbeingadeathtrap.1.Eachwinterholidaymakersinthemountainscomefacetofacewithdeathbecause（）.2.Accordingtothewriter,skiingconditionsintheSalzburgareaofAustriabeforetheaccidenthappenedwere（）.3.Inareaswhereavalanchesareknowntohappen（）.4.Althoughaccidentsdohappen,skierswillbereasonablysafeif（）.问题1选项A.theyfailtorealizehowdangerousavalanchescanbeB.theyarenotexpertenoughatskiingonthefixedruns.C.theyaretryingtoavoidareaswhereavalancheshappenD.theyskigreatdistancesdownthemountainsides问题2选项A.perfectfor,theinexperiencedskierB.unsafebecausethenewsnowwascoveredwithiceC.typicalofconditionsresultinginavalanchesD.suitableonlyforskiinglocally问题3选项A.localresidentsstayindoorswhentheweatherisbad.B.measuresaretakentopreventseriousavalanchesC.smallavalanchescaneasilybepreventedD.skiersformthemselvesintoawalltokeepthesnowinposition问题4选项A.theystayontheofficiallyapprovedslopesB.theyskionlyforpleasureC.theyskionlyatresortsD.theychooselesscrowdedskislope.12.单选题PenguinsdonotsufferfromthecoldinAntarcticabecausetheirfeathers（）aprotectiveoil.问题1选项A.secreteB.warmC.hideD.absorb13.单选题Scientificevidencefromdifferent（）demonstratesthatinmosthumansthelefthemisphereofthebraincontrolslanguages.问题1选项A.principlesB.groundsC.disciplinesD.rules14.单选题ManyfarmsintheSouthernUnitedStates（）hayandtobaccoandexportthemtootherpartsofthecountry.问题1选项A.storeB.fertilizeC.sowD.yield15.单选题Forcenturiescoalhasbeenoneofthemostimportantfuels,anditstillis,althoughitislessimportantnowthanitoncewas.Otherfuels,notablypetroleumandnaturalgas,arereplacingit.Butcoalisstillwidelyusedfordomesticheatingandinpowerstationsforgeneratingelectricity.Enormousquantitiesofcoalaremadeintogas,andforuseinmetal-smeltingfurnaces,andelsewhere.Andcoalprovidesvaluablerawmaterialsforthechemicalindustry,too.Buthereagain,petroleumandnaturalgasaresupplantingcoal.Weminecoalfromtheground,justasweminemineralsandores.Thedepositsmaylieonorjustbelowthesurfaceordeepunderground.Itisincoal-miningthatthegreatestadvancesinminingmethodshavetakenplace.Continuousminingmachineshewthecoalfromthecoalface,whereoncetheminersslaved.Lengthyconveyorsystemsconveyawaythehewcoal.Dieselandbatterylocomotiveshaulwagonsalongmilesofundergroundtunnels.Wetendtocallcoalamineral,too.Butthereisagreatdifferencebetweencoaland,say,ironore.Ironoreisinorganicinorigin,beingformedasaresultofinorganic,ornon-livingprocessesinsidetheEarth'scrust.Coal,ontheotherhand,isorganicinorigin,beingderivedfromplantswhichoncelivedonthesurface.Itconsistsmainlyofcarbon.Theactualproportionofcarbonvariesfromonetypeofcoaltoanother.MostofthecoalintheworldisderivedfromplantsthatgrewintheCarboniferousPeriodoftheEarth'shistory,whichlastedfromabout350milliontoabout280millionyearsago.DuringthisperiodwholeregionsoftheEarthwerecoveredinswamps,inwhichlivedgiganticfernsandtrees.Theplantsdiedandfellintotheswamps.Bacteriaacteduponthedeadvegetablematterandcausedittodecay.Astimewenton,thedecomposingvegetablematterbecamecoveredwithmudandclay,andthenmoreplantsgrew,died,decayed,andsoon.Inplaceslayeruponlayerofdecayedplantremainsbuiltup,sandwichedbetweenmudandclaysediments.IntimetheEarth'scrustfoldedthiswayandthat;heatandpressurechangedthesedimentsintorockandforcedoutmostofthewaterfromthedecayedmatter,whichchangedintocoal.Thuswerethecoalmeasuresformed.Notallthecoalwassubjectedtothesamedegreesofheatandpressure.Thereforetherearedifferentkindsofcoals.Peatisnotreallyatruecoal,butitrepresentsthefirstdecompositionstageinthecoal-formingprocess.Lignite,orbrowncoal,representsafurtherstateintheprocess.Itcontainsalittlelessmoisture,andsomewhatmorecarbonthanpeat.Nextthereisbituminousorsoftcoal,themostple