典型技巧12段落大意的概括分析【考情角度】考情分析自然生态类说明文中常包含人与动植物、自然与环境类主题，结构层次清晰，常为总分或总分总结构。考查角度常考查细节理解题、写作意图题、主旨大意题或段落大意题。【真题再现】(2019·浙江高考·C) 主题语境：自然生态Californiahaslosthalfitsbigtreessincethe1930s,accordingtoastudytobepublishedTuesdayandclimatechangeseemstobeamajorfactor(因素).Thenumberoftreeslargerthantwofeetacrosshasdeclinedby50percentonmorethan46,000squaremilesofCaliforniaforests,thenewstudyfinds.Noareawasor，fromthefoggynortherncoasttotheSierraNevadaMountainstotheSanGabrielsaboveLosAngeles.IntheSierrahighcountry,thenumberofbigtreeshasfallenbymorethan55percent;inpartsofsouthernCaliforniathedeclinewasnearly75percent.Manyfactorscontributedtothedecline,saidPatrickMcIntyre,anecologistwhowastheleadauthorofthestudy.Woodcuttersbigtrees.Housingdevelopmentpushedintothewoods.AggressivewildfirecontrolhasleftCaliforniaforestscrowdedwithsmalltreesthatcompetewithbigtreesforresources(资源).ButincomparingastudyofCaliforniaforestsdoneinthe1920sand1930swithanotheronebetween2001and2010,McIntyreandhiscolleaguesawidespreaddeathofbigtreesthatwasevidenteveninwildlandsprotectedfromwoodcuttingordevelopment.Thelossofbigtreeswasgreatestinareaswheretreeshadsufferedthegreatestwater.Theresearchersfiguredoutwaterstresswithacomputermodelthatcalculatedhowmuchwatertreesweregettinghowmuchtheyneeded,takingintoaccountsuchthingsasrainfall,airtemperature,ofsoil,andtheofsnowmelt(融雪).Sincethe1930s,McIntyresaid,thebiggestfactorswaterstressinthestatehavebeenrisingtemperatures,whichcausetreestolosemorewatertotheair,andearliersnowmelt,whichreducesthewatersupplyavailabletotreesduringthedryseason.\n1.Whatisthesecondparagraphmainlyabout?A.TheseriousnessofbigtreelossinCalifornia.B.TheincreasingvarietyofCaliforniabigtrees.C.ThedistributionofbigtreesinCaliforniaforests.D.TheinfluenceoffarmingonbigtreesinCalifornia.2.Whichofthefollowingis？A.Ecologicalstudiesofforests.B.Banningwoodcutting.C.Limitinghousingdevelopment.D.Firecontrolmeasures.3.WhatisaaccordingtoMcIntyre?A.Inadequatesnowmelt.B.Alongerdryseason.C.Awarmerclimate.D.Dampnessoftheair.4.Whatcanbeasuitabletitleforthetext?A.California'sForests:WhereHaveAlltheBigTreesGone?B.CuttingofBigTreestoBeProhibitedinCaliforniaSoonC.WhyAretheBigTreesImportanttoCaliforniaForests?D.PatrickMcIntyre:GrowMoreBigTreesinCalifornia答案与解析 1.A 2.D 3.C 4.A1.由第二段中关键信息“declinedby50percent,fallenbymorethan55percent,thedeclinewasnearly75percent”可知，该段主要说明树木数量减少的严重性。2.由题干关键词badforbigtrees，定位原文说明的大树数量锐减的因素。由第三段最后一句过度的野火控制使加州森林长满与大树竞争的小树苗，由此可判断出答案。3.题干关键词majorcause是原文biggestfactors的同义转述，最后一段中提到的气温升高和积雪过早融化是缺水的主要原因。由此可推出正确答案。4.根据文章关键词losthalfitsbigtrees，结合对树木减少的原因分析可确定文章标题。【技巧释义】抓关键词，兼顾段落首尾，定段落大意►提出事实：加州大树数量减少►利用数字说明加州森林树木数量锐减的现状►第3～6段说明树林数量减少的原因：伐木建房、过度的野火控制、缺水、气候变化。►文章多次出现decline,loss,fall等表“下降”的词汇，文章主题句及标题句应体现“下降”这一点。\n【词汇积累】targetvt.把……作为攻击目标documentvt.记录unaffectedadj.未受影响的shortagen.短缺dampnessn.潮气timingn.时间sparevt.留出；匀出incomparisonwith与……比较driveup迫使……快速上升 【技巧演练】（建议用时：45分钟）1Thinkaboutwhatyoudidthismorning.Yougetoutofbedandgetyourselfreadyfortheday.Manypeopletakeforgrantedthefactthattheyareabletodothisindependently.Imagineforamomentthatyoucouldn'tdressyourselformakeyourownbreakfast.Nowimagineifthisishowyouwillwakeupfortherestofyourlife.ForIvyKrause,thisisherreality.IvyhasamedicalconditionknownasEpidermolysisBullosa(表皮溶解水泡症)，orEB,wheretheslightesttouchcanblisterandevenremoveherskin.IvyhasthemostsevereformofEBwhereherskinisaffectedbothexternallyandinternally.Simpletaskslikegoingtothetoiletandgettingdressedaremadeverydifficult.MobilityislimitedasIvy'sskinhasbecometight,andherfingershavefusedtogether,withtheonlywaytoreversethisbeingsurgery.EBisaverypainfulcondition,andwhatismostheartbreakingisknowingthatthisbeautiful,smiling,littlegirlislivinginconstantextremepain.Thisiswherecarersandtrainedbabysitterscomein.YvonneMcMullanhasbeencaringforIvyforthepast3years,andsaidithasbeenboththeworstandbestexperience."It'shard.Forher,especiallyatthisage,sheneedscontinuityofcare.Byhavingthesamenursestreatingher,Ivyknowsthatweloveandcareabout\nherasmuchasshelovesus.Butwithoutbeingthere,youdon'tknowjusthowsorrowfulitistoseeherinpain.It'sheartbreaking."Ivyisafighterinalmosteverysenseoftheword.Shehasencouragedsomanypeopletogivebacktothecommunityanddonatetocharitieswhosupportthefamiliesofyoungchildrenlivingwithdisabilities,evenjusttoshowappreciationtothegiftoflifeandopportunity.Eventhoughsheiscoveredwithbandages,herstrongwillforlifeismovingandinspiring,justlikeabutterfly,facingsomanybarrierswhichstilldoesitsbesttocomeoutofthechrysalis(蝶蛹).1.WhatiswrongwithIvyKrause?A.Shedoesn'tknowhowtocook.B.Shecan'tliveonherown.C.Sheisparticularforfood.D.Sheistoolazy.2.WhatisParagraph2mainlyabout?A.ThereasonforIvy'sillness.B.ThesymptomofIvy'sEB.C.ThecuresoftreatingEB.D.Theresearchonskin.3.WhichwordscandecribeIvy?A.Generousandencouraging.B.Optimisticandgrateful.C.Ambitiousandcaring.D.Independentandunselfish.4.Whatisthebesttitleforthetext?A.AheartbrokenbabysitterB.AstrangecaseeverfoundC.AbutterflybeneaththebandagesD.Theappreciationtothegiftoflife【答案】1.B2.B3.B4.C【分析】本文是一篇记叙文。身患表皮溶解水泡症的Ivy生活不能自理，每天生活在痛苦之中，但也依然对生活充满希望，鼓励他人回报社会。1.细节理解题。根据第一段的“Imagineforamomentthatyoucouldn'tdressyourselformakeyourownbreakfast.Nowimagineifthisishowyouwillwakeupfortherestofyourlife.ForIvyKrause,thisisherreality.”（想象一下，你不能自己穿衣，也不能自己做早餐。再想象一下，如果这就是你余生醒来的方式。对IvyKrause来说，这就是她的现实）可知，IvyKrause生活不能自理。故选B。2.主旨大意题。根据第二段的主要内容，尤其“IvyhasthemostsevereformofEBwhere\nherskinisaffectedbothexternallyandinternally.......MobilityislimitedasIvy'sskinhasbecometight,andherfingershavefusedtogether,”（Ivy患有最严重的一种表皮溶解水泡症，她的内外皮肤都受到了影响。......行动受到限制，因为Ivy的皮肤已经变得非常紧绷，她的手指也已经融合再一起）可知，本段主要陈述Ivy的表皮溶解水泡症的症状。故选B。3.推理判断题。根据倒数第二段的“Byhavingthesamenursestreatingher,Ivyknowsthatweloveandcareaboutherasmuchasshelovesus.”（通过让相同的护士看护她，Ivy知道我们对她的爱和关心正如她爱我们一样多）可知，虽然身患疾病，但Ivy还是对周围的人表达出爱意，由此可知她很乐观。根据最后一段的“Shehasencouragedsomanypeopletogivebacktothecommunityanddonatetocharitieswhosupportthefamiliesofyoungchildrenlivingwithdisabilities,evenjusttoshowappreciationtothegiftoflifeandopportunity.”（她鼓励很多人回馈社会，向帮助残疾儿童家庭的慈善机构捐款，即使只是为了表达对生命和机会的感谢）可知，即使身患疾病Ivy仍然鼓励他人回馈社会，由此可知，Ivy是一个感恩的人。综上所述，Ivy是一个乐观且知道感恩的人，故选B。4.主旨大意题。根据文章的主要内容可知，本文主要讲述身患表皮溶解水泡症的Ivy生活不能自理，每天生活在痛苦之中，但也依然对生活充满希望，病鼓励他人回报社会。再结合最后一段的“Eventhoughsheiscoveredwithbandages,herstrongwillforlifeismovingandinspiring,justlikeabutterfly,facingsomanybarrierswhichstilldoesitsbesttocomeoutofthechrysalis(蝶蛹).”（尽管身体缠满绷带，但她坚强的生命意志却令人感动，让人振奋。Ivy就像一只蝴蝶，面对重重阻碍，她仍努力冲破茧的束缚）可知，虽然全身缠满绷带，她就像是裹在茧里的蝴蝶，凭借顽强的毅力破茧而出。由此可知，“绷带下的蝴蝶”可以作为本文的最佳标题。故选C。2Fitnessjunkies(上瘾者)lockedoutofgyms,commuters(上班族)fearfulofpublictransport,andfamiliesgoingcrazyinsidetheirhomesduringthecoronaviruspandemic(冠状病毒大流行)havecreatedaboom(繁荣)inbicyclesalesunseenindecades.BicyclesalesoverthepasttwomonthssawtheirbiggestspikeintheU.S.sincetheoilcrisisofthe1970s,saidJayTownley,whoanalyzescyclingindustrytrendsatHumanPoweredSolutions.“Peoplequitefranklyhavepanicked,andthey’re\nbuyingbikesliketoiletpaper,”Townleysaid,referringtotherushtobuyessentialsliketoiletpaperandhandsanitizer(杀菌剂)thatstoressawatthebeginningofthepandemic.Thetrendismirroredaroundtheglobe,ascitieslikeManilaandRome,setupbikelanes(车道)toaccommodategrowinginterestincyclingwhilepublictransportremainsreduced.InLondon,authoritiesplantogofurtherbybanningcarsfromsomecentralhighways.Therearemultiplereasonsforthepandemicbicycleboom.Aroundtheworld,manyworkerswerelookingforanalternativetobusesandsubways.Peopleunabletogototheirgymslookedforanotherwaytoexercise.Andshut-infamiliestriedtofindawaytokeepkidsactiveduringstay-at-homeorders.Thepandemicisalsodrivingaboominelectric-assistbikes,callede-bikes,whichwereaminorpartoftheoverallmarketuntilnow.SalesatCowboy,aBelgiane-bikemaker,tripled(三倍增长)intheJanuary-Aprilperiodfromlastyear.Notably,theyspikedinBritainandFranceataroundthesametimeinMaythatthosecountriesstartedeasinglockdownrestrictions,saidChiefMarketingOfficerBenoitSimeray.JoeMinutolo,co-ownerofBarHarborBicycleShop,saidhehopesthesalesgrowthtranslatesintolong-termchange.“Peoplearehavingachancetorethinkthings,”hesaid.“Maybewe'llalllearnsomethingoutofthis,andsomethingreallygoodwillhappen.”5.Whatdoestheunderlinedword“spike”inParagraph2probablymean?A.Decline.B.Restriction.C.Increase.D.Disappearance.6.WhatcanbeknownaboutManilaandRome?A.BikeLanesaresetupforcyclists.B.Localsstillrushtobuytoiletpaper.C.Carsarebannedfromsomemainroads.D.E-bikessellmuchbetterthanothercategories.7.WhatdoesParagraph4mainlytalkabout?\nA.Theappearanceofe-bikes.B.Thereasonsforthebicycleboom.C.Thedailyactivitiesofshut-infamilies.D.Thetrafficconditionsaroundtheworld.8.Whatisthemainpurposeofthetext?A.Toencouragereaderstobuybicycles.B.Toinformreadersofthebicycleboom.C.Topresentattitudestowardsthebicycleboom.D.Tointroducethenewdevelopmentofbicycles.【答案】5.C6.A7.B8.B【分析】本文是说明文。在冠状病毒大流行期间催生了几十年来未见的自行车销售热潮。5.词句猜测题。根据第二段的“BicyclesalesoverthepasttwomonthssawtheirbiggestspikeintheU.S.sincetheoilcrisisofthe1970s(在美国，过去两个月里自行车销售见证了自20世纪70年代石油危机以来的巨大spike)”和““Peoplequitefranklyhavepanicked,andthey’rebuyingbikesliketoiletpaper,”Townleysaid,referringtotherushtobuyessentialsliketoiletpaperandhandsanitizer(杀菌剂).(Townleysaid说：“坦白说，人们已经恐慌了，他们像买厕纸一样购买自行车”，他的意思是人们争相抢购生活必需品，例如厕纸、杀菌剂)”可知，在冠状病毒大流行期间人们感到恐慌，像抢购生活必需品一样争相抢购自行车。由此可知，在过去的两个月里自行车销量大涨，即划线词的意思是“上涨”。故选C。6.细节理解题。根据第三段的“Thetrendismirroredaroundtheglobe,ascitieslikeManilaandRome,setupbikelanestoaccommodategrowinginterestincyclingwhilepublictransportremainsreduced.(这一趋势在全球各地都得到了反映，例如Manila和罗马等城市建立了自行车道，以满足人们对骑车日益增长的兴趣，而公共交通仍然在减少)”可知，在Manila和Rome建了自行车车道。故选A。7.主旨大意题。分析段落结构可知，本段是总——分结构，即第一句为中心句。根据第一句“Therearemultiplereasonsforthepandemicbicycleboom.(自行车大流行的热潮有多种原因)”可知，本段主要说明自行车销售热潮的各种原因。故选B。8.推理判断题。根据文章的主要内容，尤其第一段的“familiesgoingcrazyinsidetheir\nhomesduringthecoronaviruspandemic(冠状病毒大流行)havecreatedaboom(繁荣)inbicyclesalesunseenindecades.(冠状病毒大流行在室内待到发疯的家庭创造了几十年来前所未见的自行车销售热潮)”可知，本文是说明文，旨在向读者介绍在冠状病毒大流行期间出现的自行车销售热潮现象。故选B。3Nexttimeyougoonholiday,it'sgoingtofeelprettydifferent.Youmayhavetowearafacemask.Andthatmeansgettingyourpointacrossinanunfamiliarlanguage—allwhilekeepingyourmouthcovered—couldbecomeabitofaproblem.That'swheretheC-mask,byJapanesecompanyDonutRobotics,comesin.It'sasmart,Internet-connectedmouthcoveringthatcanmakecalls,raisethewearer’svoice,andmosthelpfullyfortravelers,translateconversationsintoeightdifferentlanguages.Ifneedbe,yousimplyplaceitoverastandardfacemaskandconnectitviaBluetoothtoasmartphone.Aspecialappwillthenallowyoutorecordliveconversations,turnthemintotextandtranslatethemintoEnglish,Chinese,French,Korean,Thai,Indonesian,SpanishorVietnamese(currentlyonlyfromJapanese)—makingiteasytounderstandwhatpeoplearesaying.Itwon'tactuallyspeakthetranslatedphrasesforyou,butitdoeshaveabuilt-inamplifier（扩音器）tohelpyoumakeyourselfheard.“Weworkedhardforyearstodeveloparobotandwehaveusedwhatwe'veresearchedtocreateaproductthatrespondstohowCOVID-19hasreshapedsociety,''Donut'sCEOrecentlytoldreporters.Thefirmhasalreadyraisedmorethan28millionyenviacrowdfundingtodeveloptheproduct,whichwillgoonsalefor3,980yeninJapan.Thereareallmanneroffashionable,eco-friendlymasksyoucannowgetyourhandson—checkouttheseinLondon,SingaporeandBarcelona.Butincreatinganaffordable,high-techmask,Donutcouldwellbeontosomething.9.TheC-maskisdevelopedto_______.A.seekfashion.B.reshapesociety.C.replacecellphones.D.promotecommunication.\n10.What’sthemainideaofParagraph3?A.HowtheC-maskspeaks.B.HowtheC-maskworks.C.WhatadvantagestheC-maskbrings.D.WhatlanguagestheC-masktranslates.11.Whatdoestheunderlinedphrase"beontosomething"inthelastparagraphmean?A.takealook.B.earnaliving.C.makeadifference.D.issueawarning.12.Inwhichcolumnofawebsitedoweprobablyreadthistext?A.Health.B.Tourism.C.Fashion.D.Technology.【答案】9.D10.B11.C12.D【分析】这是一篇说明文。文章主要介绍了日本DonutRobotics研发的一种可以促进交流的高科技智能口罩，包括它的工作原理和市场等。9.推理判断题。根据一段的“Youmayhavetowearafacemask.Andthatmeansgettingyourpointacrossinanunfamiliarlanguage—allwhilekeepingyourmouthcovered—couldbecomeabitofaproblem.”（你不得不带上口罩。那就意味着要用一种不熟悉的语言表达你的观点——同时你的嘴要捂住——这可能是一个问题。）以及第二段的“That'swheretheC-mask,byJapanesecompanyDonutRobotics,comesin.”（这就是日本DonutRobotics公司生产C-mask发挥作用的地方。）可推知，研发C-mask主要是为了促进交流。故选D。10.主旨大意题。根据第三段的“Ifneedbe,yousimplyplaceitoverastandardfacemaskandconnectitviaBluetoothtoasmartphone.Aspecialappwillthenallowyoutorecordliveconversations,turnthemintotextandtranslatethemintoEnglish,Chinese,French,Korean,Thai,Indonesian,SpanishorVietnamese(currentlyonlyfromJapanese)”（如果有需要，你只需要将它戴在标准的口罩上，并通过蓝牙连接到智能手机上。然后，一个特殊的应用程序将允许你记录现场对话，把它们转化成文本和翻译成英语、中文、法语、韩语、泰语、印尼语、西班牙语或者越南语（目前只限日语））可知，本段主要讲述了C-mask的工作原理。故选B。11.词句猜测题。根据最后一段的“Thereareallmanneroffashionable,eco-friendly\nmasksyoucannowgetyourhandson—checkouttheseinLondon,SingaporeandBarcelona.Butincreatinganaffordable,high-techmask,Donutcouldwellbeontosomething.”可知，你可以在伦敦、新加坡和巴塞罗那买到各种时尚、环保的口罩。但开发一个负担得起的、高科技的口罩，Donut可能非常beontosomething。根据句意可知，上下文为转折意义，上文说时尚环保的口罩随处能买，故推测Donut公司研发价格合理的高科技口罩真的是非常了不起的，能给人们带来了很大的影响。即划线部分的意思是“有影响”。故选C。12.推理判断题。根据文章第二段“That'swheretheC-mask,byJapanesecompanyDonutRobotics,comesin.It'sasmart,Internet-connectedmouthcoveringthatcanmakecalls,raisethewearers’voice,andmosthelpfullyfortravelers,translateconversationsintoeightdifferentlanguages.”(这就是日本DonutRobotics公司生产C-mask发挥作用的地方。这种智能联网的口罩可以打电话、提高佩戴者的声音，同时也为旅行者提供了帮助，可以将谈话翻译成八种语言。)可知，文章主要介绍了一种高科技的智能口罩，属于科技范畴，因此本文很有可能出现在网页的科技版面。故选D。4WhatiftheMoonhadneverexisted?ForstartersweknowthatthegeophysicalandclimatologicalhistoryoftheEarthwouldhavebeendifferent.AlthoughthereisstilllargeuncertaintyabouthowtheMoonwasformed,themostcurrentlyfavoredtheorydescribesadisastrouscollisionbetweentheEarthandanotherplanetaryobject.ThateventforeverchangedmanyaspectsoftheEarth'sevolution.Forexample,witharelativelylargenaturalsatelliteputtinggravitationaltidalforces(潮汐力)onit,theEarth'sspinbehaviorhasbeenquitedifferentthanitwouldhavebeenotherwise.Daylengthhasincreasedmorerapidlythanwithoutamoon.AndthenaturalchangesinthedirectionoftheEarth'sspinaxis(轴)-itspoles-havebeenlessthantheywouldhavebeenotherwise.AshorterdaylengthandaxialvariationslikethesewouldhavechangedtheEarth'sclimatehistory,andalmostcertainlyhavechangedthewayanylifeevolved.Butifaspecieslikeushadstillappeared,itslandscapeforspaceexplorationwouldalsohavebeencompletelydifferent.Withoutalargenaturalsatellite,amere\nquarterofamillionmilesaway,therewouldhavebeenno"easy"triptomaketoanotherworld.Iftherehadbeenafirsthumanmissiontoanotherworld,itwouldlikelyhavebeentoMars.Butthiswouldsurelyhavecalledforfarmoreextensivedesigningofspacecraftandlife-supportsystemsfordeepspace.PerhapsinsteadtheinitialfocuswouldhavebeenentirelyonEarth-orbitingequipmentforpeopleandroboticmissionstootherworlds.Or,maybetheattractionoftheseeminglynearimpossiblewouldstillhaveencouragedthesehumansfromanalternaterealitytotakethegreatleaptoMarsastheirfirststepoutwards.Itisofcourse,impossibletoknowexactlywhatourworldwouldreallybelikewithouttheMoon-bothphysically,andintermsofhumanexploration.Butonethingdoesseemclear:weprobablytakeournaturalsatellite'sexistencefartoomuchforgranted.Noteveryinhabitedplanetintheuniversewillhaveitsownready-madegatewaytotheuniverse.13.Whydoestheauthorusethequestionattheverybeginning?A.Tointroducethewidelyacceptedtheory.B.Tomentionthedestructivecollision.C.Toproveawrongassumption.D.Toattractreaders'interest.14.WhatdoestheauthorintendtodoinParagraph2?A.Comparedaylengthsindifferentclimates.B.IntroducetheevolutionoflifeontheEarth.C.ExplainwhytheEarth'sspinbehaviorremains.D.ShowhowtheMoongreatlyinfluencestheEarth.15.Whatdoestheunderlinedword"this"inParagraph3referto?A.TheEarth'sevolution.B.ThemissiontoMars.C.ThetriptotheMoon.D.Earth-orbitingequipment.16.What'stheauthor'spurposeinwritingthetext?A.TocallonpeopletostudytheEarth.B.TostressthesignificanceoftheMoon.C.Tospeakhighlyofhumanexploration.D.ToproveassumptionsaboutmoonlessEarth.\n【答案】13.D14.D15.B16.B【分析】这是一篇说明文。文章强调了月球对地球的重大影响和重要性。【详解】1.推理判断题。根据第一段“WhatiftheMoonhadneverexisted?ForstartersweknowthatthegeophysicalandclimatologicalhistoryoftheEarthwouldhavebeendifferent.AlthoughthereisstilllargeuncertaintyabouthowtheMoonwasformed,themostcurrentlyfavoredtheorydescribesadisastrouscollisionbetweentheEarthandanotherplanetaryobject.”（如果月球从未存在过呢?首先，我们知道地球的地球物理和气候学历史会有所不同。尽管月球是如何形成的还存在很大的不确定性，但目前最受欢迎的理论描述了地球和另一个行星物体之间的灾难性碰撞。）可知，作者做出假设“如果没有月球，地球会如何”以及讨论月球的形成原因从而引起读者兴趣。故选D。2.推理判断题。第二段中作者描述了月球改变了地球进化的各个方面，并且举了例子。再根据最后一句“AshorterdaylengthandaxialvariationslikethesewouldhavechangedtheEarth'sclimatehistory,andalmostcertainlyhavechangedthewayanylifehasevolved.”（像这样更短的白昼长度和轴向变化将会改变地球的气候历史，几乎肯定会改变任何生命进化的方式。）可知，第二段作者是想描述月亮对地球的影响有多大。故选D。3.词义猜测题。根据第三段第三句“Iftherehadbeenafirsthumanmissiontoanotherworld,itwouldlikelyhavebeentoMars.”（如果人类第一次去另一个世界执行任务的话，很可能是去火星。）可知this指“去火星的任务”，故选B。4.主旨大意题。文中前三段的假设皆在说明月球对地球和人类很重要，最后一段强调没有月球的世界难以想象。所以作者是想要强调月球的重要性。故选B项。
