職稱英語真題理工A

------------------------------------/shiti/59.html------------------------------------職稱英語真題理工A2013年度全國職稱英語等級考試理工類（A級）試題及參考答案第1部分：詞匯選項（第1～15題，每題1分，共15分）下面每個句子中均有1個詞或短語劃有橫線，請為每處劃線部分確定1個意義最為接近的選項。1.Therulesaretoorigidtoallowforhumanerror.A.inflexibleB.generalC.complexD.direct2.Thisspecieshasnearlydiedoutbecauseitshabitatisbeingdestroyed.A.turneddeadB.passedbyC.carriedawayD.becomeextinct3.Thecontractbetweenthetwocompanieswillexpiresoon.A.shortenB.endC.startD.resume4.Threeworld-classtennisplayerscametocontentforthistitle.A.argueB.claimC.wishD.compete5.Themethodsofcommunicationusedduringthewarwereprimitive.A.simpleB.reliableC.effectiveD.alternative6.Respectforlifeisacardinalprincipleofthelaw.A.moralB.regularC.fundamentalD.hard7.Thedrinkingwaterhasbecamecontaminatedwithlead.A.pollutedB.treatedC.testedD.corrupted8.Comeout,orI’llbustthedoordown.A.shutB.setC.breakD.beat9.Sheshedafewtearsatherdaughter’swedding.A.wipedB.injectedC.producedD.removed10.Theydidn’tseemtoappreciatethemagnitudeoftheproblem.A.existenceB.importanceC.causeD.situation11.Thetowerremainsintacteveraftertwohundredyears.A.unknownB.unusualC.undamagedD.unstable12.Manyexpertsremainskepticalabouthisclaims.A.doubtfulB.untouchedC.certainD.silent13.Theproposalwasendorsedthemajorityofmembers.A.rejectedB.submittedC.consideredD.approved14.Rumorsbegantocirculateabouthisfinancialproblems.A.sendB.spreadC.hearD.confirm15.Thepolicewillneedtokeepawaryeyeonthisareaoftown.A.nakedB.cautiousC.blindD.private參考答案：1.A2.D3.B4.D5.A6.C7.A8.C9.C10.B11.C12.A13.D14.B15.B第2部分：閱讀判斷（第16～22題，每題1分，共7分）下面的短文后列出了7個句子，請根據(jù)短文的內容對每個句子做出判斷：如果該句提供的是正確信息，請選擇A；如果該句提供的是錯誤信息，請選擇B；如果該句的信息文中沒有提及，請選擇C。KickingtheHabitWhatisabadhabit?Themostdefinitionisthatitissomethingthatwedoregularly,almostwithoutthinkingaboutit,andwhichhassomesortofnegativeconsequence.Thisconsequencecouldaffectthosearoundus,oritcouldaffectuspersonally.Thosewhodenyhavingbadhabitsareprobablylying.Badhabitsarepartofwhatmakesushuman.Manyearlyhabits,likesuckingoutthumb,arebrokenwhenweareveryyoung.Weareeithertoldtostopdoingitbyourparents,orweconsciouslyorsubconsciouslyobservethatothersdonothavethesamehabit,andwegraduallygrowoutofit.Itiswhenweintentionallyorunintentionallypickupnewhabitsinourlaterchildhoodorearlyadulthoodthatitbecomesaproblem.Unlesswecanbreakthathabitearlyon,itbecomesapartofoutlife,andbecomes“programmed”intoourbrain.Arecentstudyofhumanmemorysuggeststhatnomatterhowhardwetrytochangeouthabits,itistheoldwaysthattendtowin,especiallyinsituationswherewearerushed,stressedoroverworked.Habitsthatwethoughtwehadgotridofcansuddenlycomeback.Duringthestudyprogram,theresearchersshowedagroupofvolunteersseveralpictures,andgavethemwordstoassociatewiththem.Theythenshowedthevolunteersthesamepictureagain,andgavethemnewwordstoassociatewiththem.Afewdayslater,thevolunteersweregivenatest.Theresearchersshowedthemthepictures,andtoldthemtorespondwithoneofthewordstheyhadbeengivenforeachone.Itcameasnosurprisethattheiranswersweresplitbetweenthefirstsetofwordsandsecond.Twoweekslater,theyweregiventhesametestagain.Thistime,mostofthemonlygavethefirstsetofwords.Theyappearedtohavecompletelyforgottenthesecondset.Thestudyconfirmsthattheresponseswelearnfirstarethosethatremainstrongestovertime.Wemaytrytochangeoutways,butafterawhile,theresponsethatcomestomindfirstisusuallythefirstonewelearned.Themorethatresponseisused,themoreautomaticitbecomesandtheharderitbecomestorespondinanyotherway.Thestudythereforesuggeststhatovertime,ourbadhabitsalsobecomeautomatic,learnedbehavior.Thisisnotgoodnewsforpeoplewhopickupbadhabitsearlyinlifeandnowwanttochangeorbreakthem.Evenwhenwetrytoputnew,goodintentionsintopractice,thosepreviouslearnedhabitsremainstrongerinmoreautomatic,unconsciousformsofmemory.16.Boysusuallydevelopbadhabitswhentheyareveryyoung.A.RightB.WrongC.Notmentioned17.Wecanonlybreakbadhabitsifotherstellustodo.A.RightB.WrongC.Notmentioned18.Badhabitsmayreturnwhenweareunderpressure.A.RightB.WrongC.Notmentioned19.Researchersweresurprisedbytheanswerthatthevolunteersgaveinthefirsttest.A.RightB.WrongC.Notmentioned20.Thevolunteersfoundthetestmoredifficultwhentheydiditthesecondtime.A.RightB.WrongC.Notmentioned21.Thestudysuggeststhatitismoredifficulttorespondwhattogetridof.A.RightB.WrongC.Notmentioned22.Ifwedevelopbadhabitsearlyinlife,theyarehardertogetridof.A.RightB.WrongC.Notmentioned參考答案：16.A17.B18.A19.B20.C21.B22.A第3部分：概括大意與完成句子（第23～30題，每題1分，共8分）下面的短文后有2項測試任務：（1）第23～26題要求從所給的6個選項中為第1～4段每段1選擇個最佳標題；（2）第27～30題要求從所給的6個選項中為每個句子確定1個最佳選項。BlackHoles1Blackholescanbebestdescribedasasortofvacuum,suckingupeverythinginspace.Scientistshavediscoveredthatblackholescomefromanexplosionofhugestars.Starsthatareneardeathcannolongerburnduetolossoffuel,andbecauseitstemperaturecannolongercontrolthegravitational(重力的)force,hydrogenendsupputtingpressureontothestar’ssurfaceuntilitsuddenlyexplodesthencollapses.2Blackholescomefromstarsthataremadeofhydrogen,othergasesandafewmetals.Whentheseexplodeitcanturnintoastellar-mass(恒星質量)blackhole,whichcanonlyoccurifthestarislargeenough(shouldbebiggerthanthesun)fortheexplosiontobreakitintopieces,andthegravitystartstocompacteverypieceintothetiniestparticle.Trytoseeandcompare:ifastarthat’stentimesthesizeofthesunendupbeingablackholethat’snolongerthan70kilometers,thentheEarthwouldbecomeblackholethat’sonlyafractionofaninch!3Objectsthatgetsuckedinablackholewillalwaysremainthere,nevertobreakfree.Butrememberthatblackholescanonlygobbleup(吞噬)objectswithinaspecificdistancetoit.It’spossibleforalargestarnearthesuntobecomeablackhole,butthesunwillcontinuetostayinplace.Orbits(軌道)donotchangebecausethenewlyformedblackholecontainsexactlythesameamountofmassaswhenitwasastar,onlythisitsmassistotallycontractedthatitcanendupasnobiggerthanastate.4Sofar,astronomershavefiguredoutthatblackholesexistbecauseofAlbertEinstein’stheoryofrelativity.Intheend,throughnumerousstudies,theyhavediscoveredthatblackholestrulyexist.Sinceblackholestraplightanddonotgiveofflight,itisnotpossibletodetectblackholesviaatelescope.Butastronomerscontinuetoexploregalaxies(銀河系),spaceandthesolarsystemtounderstandhowblackholes.Itispossiblethatblackholescanexistformillionsofyears,andlatercontributefurtherprocessingalaxies,whichcaneventuallyleadtocreationofnewentities.Scientistsalsocreditblackholesashelpfulinlearninghowgalaxiesbegantoform.23Paragraph1________24Paragraph2________25Paragraph3________26Paragraph4________AIsthereproofthatblackholesreallyexist?BWhataredifferenttypesofblackholes?CHowareblackholesformed?DHowwereblackholesnamed?EWhathappenedtotheobjectsaroundablackhole?FWhatareblackholesmadeof?27Blackholesareformedafter______.28Whenalargestarexplodes,thegravitycompactseverypieceinto______.29Anewlyformedblackholeandthestaritcomesfromareof______.30AlbertEinstein’stheoryofrelativityhelpstoprove______.AthecreationofnewentitiesBanexplosionofhugestatsCthethinnestparticleDthesameamountofmassEtheexistenceofblackholesFafractionofaninch參考答案:23.C24.F25.E26.A27.B28.C29.D30.E第4部分：閱讀理解（第31~45題，每題3分，共45分）下面有3篇短文，每篇短文后有5道題，每道題后面有4個選項。請根據(jù)文章的內容，從每題所給的4個選項中選擇1個最佳答案，涂在答題卡相應的位置上。第一篇ForecastingMethodsThereareseveraldifferentmethodsthatcanbeusedtocreateaforecast.Themethodaforecasterchoosesdependsupontheexperienceoftheforecaster,theamountofinformationavailabletotheforecaster,thelevelofdifficultythattheforecastsituationpresents,andthedegreeofaccuracyorconfidenceneededintheforecast.Thefirstofthesemethodsisthepersistencemethod;thesimplestwayofproducingaforecast.Thepersistencemethodassumesthattheconditionsatthetimeoftheforecastwillnotchange,Forexample,ifitissunnyand87degreetoday,thepersistencemethodpredictsthatitwillbeSunnyand87degreetomorrow.Iftwoinchesofrainfelltodaythepersistencemethodwouldpredicttwoinchesofrainfortomorrow.However,ifweatherconditionschangesignificantlyfromdaytoday,thepersistencemethodusuallybreaksdownandisnotthebestforecastingmethodtouse.Thetrendsmethodinvolvesdeterminingthespeedanddirectionofmovementforfronts,highandlowpressurecenters,andareasofcloudsandprecipitation(降水量).Usingthisinformation,theforecastercanpredictwhereheorsheexpectsthosefeaturestobeatsomefuturetime.Forexample,ifastormsystemis1000mileswestofyourlocationandmovingtotheeastat250milesperday,usingthetrendsmethodyouwouldpredictittoarriveinyourareain4days,Thetrendsmethodworkswellwhensystemscontinuetomoveatthesamespeedinthesamedirectionforalongperiodoftime.Iftheyslowdown,speedup,changeintensity,orchangedirection,thetrendsforecastwillprobablynotworkaswell.Theclimatology(氣候學)methodisanothersimplewayofproducingaforecast.Thismethodinvolvesaveragingweatherstatisticsaccumulatedovermanyyearstomaketheforecast.Forexample,ifyouwereusingtheclimatologicmethodtopredicttheweatherforNewYorkCityonJuly4th,youwouldgothroughalltheweatherdatathathasbeenrecordedforeveryJuly4thandtakeanaverage.Theclimatologicmethodonlyworkswellwhentheweatherpatternissimilartothatexpectedforthechosentimeofyear.Ifthepatternisquiteunusualforthegiventimeofyear,theclimatologicmethodwilloftenfail.Theanalogmethodisaslightlymorecomplicatedmethodofproducingaforecast.Itinvolvesexaminingtoday’sforecastscenario(模式)andrememberingadayinthepastwhentheweatherscenariolookedverysimilar(ananalog)Theforecasterwouldpredictthattheweatherinthisforecastwillbehavethesameasitdidinthepast,theanalogmethodisdifficulttousebecauseitisvirtuallyimpossibletofindapredictanalog.Variousweatherfeaturesrarelyalignthemselvesinthesamelocationstheywereintheprevioustime.Evensmalldifferencesbetweenthecurrenttimeandtheanalogcanleadtoverydifferentresults.31Whichofthefollowingfactorsisnotmentionedinchoosingaforecastingmethod?A.Necessaryamountofinformation.B.Degreeofdifficultyinvolvedinforecasting.C.Practicalknowledgeoftheforecaster.D.Creativityoftheforecaster.32Thepersistencemethodfailstoworkwellwhen_____.A.itisrainyB.itissunnyC.weatherconditionsstaystableD.weatherconditionschangegreatly33Thetrendsmethodworkswellwhen_____.A.weatherconditionsareconstantforalongperiodoftimeB.weatherconditionsaredefinedwellenoughC.predictiononprecipitationareaccurateD.thespeedanddirectionofmovementarepredicable34Theanalogmethodshouldnotbeusedinmakingaweatherforecastwhen_____.A.theanaloglookscomplicatedB.thecurrentweatherscenarioisdifferentfromtheanalogC.theanalogismorethan10yearsoldD.thecurrentweatherscenarioisexactlythesameastheanalog35Historicalweatherdataarenecessaryin_____.A.thepersistencemethodandthetrendsmethodB.thetrendsmethodandtheclimatologymethodC.theclimatologymethodandtheanalogmethodD.thepersistencemethodandtheanalogmethod參考答案:31.D32.D33.A34.B35.C第二篇StudentsLearnBetterwithTouchscreenDesksObservethecriticismsofnearlyanymajorpubliceducationsystemintheworld,andafewofthemanycomplaintsaremoreorlessuniversal.Technologymovesfasterthantheeducationsystem.Teachersmustteachatthepaceofthesloweststudentratherthanthefastest.And—particularlyintheUnitedStates—gradeschoolchildrenasagroupdon’tcaremuchfor,orexcelat,mathematics.Soit’shearteningtolearnthatanewkindof“classroomofthefuture”showspromiseatmitigatingsomeoftheseproblems,startingwiththatfundamentalpieceofclassroomfurniture:thedesk.AUKstudyinvolvingroughly400students,mostlyaged8-10years,andanewgenerationofmulti-touch,multi-user,computerizeddesktopsurfacesisshowingthatoverthelastthreeyearsthetechnologyhasappreciablyboostedstudents’mathskillscomparedtopeerslearningthesamematerialviatheconventionalpaper-and-pencilmethod.How?Throughcollaboration,mostly,aswellasbygivingteachersbettertoolsbywhichtomicromanageindividualstudentswhoneedsomeextrainstructionwhileallowingtherestoftheclasstocontinuemovingforward.Science,ClayDillow,classroomofthefuture,education,engineering,math,mathematics,SynergyNetTraditionalinstructionstillshowsrespectableefficacy(效力)atincreasingstudentsfluencyinmathematics,essentiallythroughmemorizationandpractice—dull,repetitivepractice.Buttheresearchershaveconcludedthatthesenewtouchscreendesksboostbothfluencyandflexibility—thecriticalthinkingskillsthatallowstudentstosolvecomplexproblemsnotsimplythroughknowingformulasanddevices,butbybeingabletofigureoutwhattherealproblemisandthemosteffectivemeansofstrippingitdownandsolvingit.Onereasonforthis,theresearcherssay,isthemulti-touchaspectofthetechnology.Studentsworkinginthenext-genclassroomcanworktogetheratthesametabletop,eachofthemcontributingandengagingwiththeproblemaspartofagroup.KnownasSynergyNet,thesoftwareusescomputervisionsystemsthatseeintheinfrared(紅外線)spectrumtodistinguishbetweendifferenttouchesondifferentpartsofthesurface,allowingstudentstoaccessandusetoolsonthescreen,moveobjectsandvisualaidsaroundontheirdesktops,andotherwisephysicallyinteractwiththenumbersandinformationontheirscreens.Byusingthesescreenscollaboratively,theresearcherssay,thestudentsaretosomeextentteachingthemselvesasthosewithastrongergraspondifficultconceptspullotherstudentsforwardalongwiththem.36WhichofthefollowingisNOTtrueofthepubliceducationsystem?AItdoesnotcatchupwiththedevelopmentoftechnology.BTeacherspaymoreattentiontofastlearnersthanslowlearners.CSomesimilarcomplaintsaboutitareheardindifferentcountries.DManystudentsarenotgoodatlearningmathematics.37Whathasbeenfoundafterthenewtechisemployed?ATeachersareabletogiveindividualizedattentiontostudentsinneed.BStudentsbecomelessactiveinlearningmathematics.CStudentsshowpreferencetotheconventionalpaper-and-pencilmethod.DThegapbetweenslowlearnersandfastlearnersgetsmorenoticeable.38Whatisthebenefitstudentsgetfromthenewtech?AItmakesthemmorefluentinpublicspeech.6BItoffersthemmoreflexibilityinchoosingcourses.CItiseffectiveinhelpingthemsolvephysicalproblems.DItenablesthemtodevelopcriticalthinkingability.39Whathappenswhenstudentsareusingthedesktopofthenewtech?AEverystudenthasanindividualtabletop.BStudentsusedifferenttoolstointeractwitheachother.CThemulti-touchfunctionstimulatesstudents.DThesoftwareinstalledautomaticallyidentifiesdifferentusers.40Howdoesthenewtechworktoimprovestudents’mathematicallearning?AIthelpsfastlearnerstolearnfaster.BItmakesteachers’instructionunnecessary.CItenablesthemtoworktogether.DItallowsthewholeclasstolearnatthesametime.參考答案:36.B37.A38.D39.C40.C第三篇OntheTrialoftheHoneyBadgerOnarecentfieldtriptotheKalahariDesert,ateamofresearcherslearnalotmoreabouthoneybadgers.TheteamemployedalocalwildlifeexpertKitsoKhamatohelpthemlocateandfollowthebadgersacrossthedesert.Theirmainaimwastostudythebadgers’movementsandbehaviorasdiscreetly(謹慎地)aspossiblewithoutfrighteningthemawayorcausingthemtochangetheirnaturalbehavior.Theyalsoplannedtotrapafewandstudythemcloseupbeforereleasingtheminviewoftheanimal’sreputation,thiswassomethingthatevenKhamawasreluctanttodo.“Theproblemwithhoneybadgersistheyarenaturallycuriousanimals,especiallywhentheyseesomethingnew,”hesays.“That,combinedwiththeirunpredictablenature,canbeadangerousmixture.Iftheysenseyouhavefood,forexample,theywon’tbeshyaboutcomingrightuptoyouforsomethingtoeat.They’reactuallyquitesociablecreaturesaroundhumans,butassoonastheyfeeltheymightbeindanger,theycanbecomeextremelyvicious(兇惡的).Fortunatelythisisrare,butitdoeshappen.”Theresearchconfirmedmanythingsthatwerealreadyknown.Asexpected,honeybadgersateanycreaturestheycouldcatchandkill.Evenpoisonoussnakes,fearedandavoidedbymostotheranimals,werenotsafefromthem.Theresearchersweresurprised,however,bytheanimal’sfondnessforlocalmelons,probablybecauseoftheirhighwatercontent.Preciouslyresearchersthoughtthattheanimalgotallofitsliquidrequirementsfromitsprey(獵物).Theteamalsolearntthat,contrarytopreviousresearchfindings,thebadgersoccasionallyformedloosefamilygroups.Theywerealsoabletoconfirmcertainresultsfrompreviousresearch,includingthefactthatfemalebadgersneversocializedwitheachother.Followingsomeofthemalebadgerswasachallenge,sincetheycancoverlargedistancesinashortspaceoftime.Somehuntingterritoriescovermorethan500squarekilometers.Althoughtheyseemhappytosharetheseterritorieswithothermales,thereareoccasionalfightsoveranimportantfoodsource,andmalebadgerscanbeasaggressivetowardseachotherastheyaretowardsotherspecies.Asthebadgersbecameaccustomedtothepresenceofpeople,itgavetheteamthetogetupclosetothemwithoutbeingthesubjectoftheanimal’scuriosity—orsuddenaggression.Thebadgers’eatingpatterns,whichhadbeendisrupted,tonormal.Italsoallowedtheteamtoobservemorecloselysomeoftheothercreaturesthatformworkingassociationswiththehoneybadger,astheseseemedtobadgers’relaxedattitudewhennearhumans.41WhydidthewildlifeexpertsvisittheKalahariDesert?A.Tofindwherehoneybadgerslive.B.Tocatchsomehoneybadgersforfood.7C.Toobservehowhoneybadgersbehave.D.Tofindoutwhyhoneybadgershaveabadreputation.42WhatdoesKitsoKhamasayabouthoneybadgers?A.Theyarealwayslookingforfood.B.Theydonotenjoyhumancompany.C.Theyshowinterestinthingstheyarenotfamiliarwith.D.Itiscommonforthemtoattackpeople.43Whatdidtheteamfindoutabouthoneybadgers?A.Thereweresomecreaturestheydidnoteat.B.Theywereafraidofpoisonouscreatures.C.Femalebadgersdidnotmixwithmalebadgers.D.Theymaygetsomeofthewatertheyneededfromfruit.44Whichofthefollowingisatypicalfeatureofmalebadgers?A.Theydon’trunveryquickly.B.Theydefendtheirterritoryfromotherbadgers.C.Theyhuntoveraverylargearea.D.Theyaremoreaggressivethanfemales.45Whathappenedwhenhoneybadgersgotusedtohumansaroundthem?A.Theybecamelessaggressivetowardsothercreatures.B.Theylostinterestinpeople.C.Theystartedeatingmore.D.Otheranimalsstartedworkingwiththem.參考答案：41.C、42.C、43.D、44.C、45.B第5部分：補全短文（第46～50題，每題2分，共10分）下面的短文有5處空白，短文后有6個句子，其中5個取自短文，請根據(jù)短文內容將其分別放回原有位置，以恢復文章原貌。ToadsareArthritisandinPainArthritis(關節(jié)炎)isanillnessthatcancausepainandswellinginyourbones.Toads(蟾蜍),abigprobleminthenorthofAustralia,aresufferingfrompainfularthritisintheirlegsandbackbone,anewstudyhasshown.Thetoadsthatjumpthefastestaremorelikelytobelargerandtohavelongerlegs._______(46)Thelargeyellowtoads,nativetoSouthandCentralAmerica,wereintroducedintothenorth-easternAustralianstateofQueenslandin1935inanattempttostopbeetlesandotherinsectsfromdestroyingsugarcanecrops.Nowupto200millionofthepoisonoustoadsexistinthecountry,andtheyarerapidlyspreadingthroughthestateofNorthernTerritoryatarateofupto60kmayear.Thetoadscannowbefoundacrossmorethanonemillionsquarekilometres._______(47)AVenezuelanpoisonviruswastriedinthe1990sbuthadtobeabandonedafteritwasfoundtoalsokillnativefrogspecies.ThetoadshaveseverelyaffectedecosystemsinAustralia.Animals,andsometimespets,thateatthetoadsdieimmediatelyfromtheirpoison,andthetoadsthemselveseatanythingtheycanfitinsidetheirmouth._______(48)Aco-authorofthenewstudy,RickShine,aprofessorattheUniversityofSydney,saysthatlittleattentionhasbeengiventotheproblemsthattoadsface.Rickandhiscolleaguesstudiednearly500toadsfromQueenslandandtheNorthernTerritoryandfoundthatthoseinthelatterstatewereverydifferent.Theywereactive,sprintingdownroadsandbreedingquickly.Accordingtotheresultsofthestudy,thefastesttoadstravelnearlyonekilometreanight._______(49)Butspeedandstrengthcomeataprice—arthritisofthelegsandbackboneduetoconstantpressureplacedonthem.Inlaboratorytests,theresearchersfoundthatafterabout15minutesofhopping,arthritictoadswouldtravelless8distancewitheachhop(跳躍)._______(50)Thesetoadsaresoprogrammedtomove,apparently,thatevenwheninpainthetoadstravelledasfastandasfarasthehealthyones,continuingtheirconstantmarchacrossthelandscape.A.Thetasknowfacingthecountryishowtoremovethetoads.B.Toadsarenotbuilttoberoadrunners——theyarebuilttositaroundpondsandwetareas.C.Butthisadvantagealsohasabigdrawback—upto10%ofthebiggesttoadssufferfromarthritis.D.Toadswithlongerlegsmovefasterandtravellongerdistanceswhiletheothersarebeingleftbehind.E.Butarthritisdidn’tslowdowntoadsoutsidethelaboratorytheresearchfound.F.Furthermore,theysoontakeoverthenaturalhabitatsofAustralia’snativespecies.參考答案:46.C47.F48.A49.D50.E第6部分：完形填空（第51~65題，每題1分，共15分）閱讀下面的短文，文中有15處空白，每處空白給出了4個選項，請根據(jù)短文的內容從4個選項中選擇1個最佳答案，涂在答題卡相應的位置上。BetterSolarEnergySystems:MoreHeat,MoreLightSolarphotovoltaicthermalenergysystems,orPVTs,generatebothheatandelectricity,but____(51)____nowtheyhaven’tbeenverygoodattheheat-generatingpartcomparedtoastand-alonesolarthermalcollector.That’sbecausetheyoperateatlowtemperaturestocoolcrystallinesiliconsolarcells,____(52)____letsthesilicongeneratemoreelectricitybutisn’taveryefficientwaytogatherheat.That’saproblemofeconomics.G