专题02 保护生物多样性 促进可持续发展-备战2023年中考英语阅读理解时文爆点专题训练（解析版）

专题02保护生物多样性促进可持续发展备战2022-2023年中考英语阅读理解时文爆点专题训练A（2022·广东深圳·校考三模）TheInternationalDayforBiologicalDiversity（生物多样性日）iscelebratedonMay22.Itsaimistoremindpeopletogetalongwiththenature.Thedaywasfirstcreatedin1993bytheUNanditwasonDecember29th.In2000,theUNchangedittoMay22.ThiswaspartlyinmemoryoftheUNconvention（公约）onMay22,1992.ButitwasalsohardformanycountriestoorganizeeventsonDecember29,becausetherearealreadymanyholidaysinthattimeoftheyear.Everyyear,thecelebrationsofthedayareorganizedonadifferenttopic.Thetopicin2022is“Buildingasharedfutureforalllife”.Themessagebehindisthatbiodiversityiswhatwecandependontobuildabrightfuture.Itisalsotheanswertoseveraldevelopmentchallenges.Biologicaldiversityarenecessaryforourdailylife.Forexample,fishprovide20%ofanimalproteintoabout3billionpeople.Over80%ofthehumandietisprovidedbyplants.Asmanyas70%ofpeoplefromcountrysideindevelopingcountriesdependontraditionalplant-basedmedicinesforbasichealthcare.Whilepeoplestarttoknowthatbiologicaldiversityisvaluable,thenumberofspecies（物种）isdroppingbecauseofhumanactivities.ThatiswhytheUNdecidedtocelebratethedayeveryyear.1．Whatdoes“it”meaninParagraph2?A．TheUN. B．Thebuilding. C．Thedate. D．Theaim.2．Whatcanwelearnfromthetopicof2022?A．Wecanbuildabrightfutureforalllifebysharing.B．Wecanusedifferentanimalstomakeourfuturebright.C．Ifwehavedifficultydeveloping,wemayturntobiodiversity.D．Iftherearefeweranimalsorplants,wewillhaveabrightfuture.3．Howmuchofthehumandietisprovidedbyplants?A．20%. B．70%. C．80%. D．100%.4．Whatisthemainideaofthelasttwoparagraphs?A．Thehistoryoftheday. B．Thecelebrationsoftheday.C．Thecausesofthedeathofanimals. D．Theimportanceofbiologicaldiversity.5．Wherecanwefindthearticle?A．Anaturemagazine. B．Astorybook. C．Aguidebook. D．Acomicbook.【答案】1．C

2．C

3．C

4．D

5．A【导语】本文是一篇说明文，主要介绍了生物多样性日。1．词句猜测题。根据“In2000,theUNchangedittoMay22”可知是将“it”改为了5月22日，推测“it”应该是指日期。故选C。2．推理判断题。根据“Themessagebehindisthatbiodiversityiswhatwecandependontobuildabrightfuture”可知我们可以依靠生物多样性来创建一个光明的未来，当发展遇到难题时，可以通过生物多样性的方法来解决。故选C。3．细节理解题。根据“Over80%ofthehumandietisprovidedbyplants.”可知超过80%的人类食物由植物提供。故选C。4．主旨大意题。根据“Biologicaldiversityarenecessaryforourdailylife”和“peoplestarttoknowthatbiologicaldiversityisvaluable”可推测最后两段主要是讲述了生物多样性的重要。故选D。5．推理判断题。根据文章大意可知，本文主要是介绍了生物多样性日的由来以及纪念日的重要性，推测文章应该来源于有关自然的杂志。故选A。B（2022·福建三明·统考模拟预测）BiodiversityConservation(生物多样性保护)inChinaChinahasalwayspaidhighattentiontobiodiversityconservation.Andyearsofeffortshavepaidoff.★ProtectedareasProtectedareasystemSincethefirstnaturereserve(保护区)wassetupin1956,Chinahasdevelopedcloseto10,000protectedareas.That’sabout18%ofChina’stotallandarea.★PopulationsofsomeendangeredanimalsinChinaAnimalPictureNumber(past)Number(now）Crestedibis(朱鹮)only7(1981)about4,400Hainangibbon(海南长臂猿)lessthan10in2groups(1980)between30and40in5groupsAsianelephant(inthewild)lessthan200(1980s)about300Giantpanda(inthewild)1,114(fortyyearsago)1,864★Theeco-environment6．WhendidChinadevelopitsfirstnaturereserve?A．In1956. B．In1980. C．In1981. D．In2021.7．HowmanywildAsianelephantsliveinChinainthe1980s?A．Only7. B．Lessthan10. C．Lessthan200. D．About1,114.8．Whichanimalhasthebiggestnumberofallnow?A．Crestedibis. B．Hainangibbon. C．Asianelephant. D．Giantpanda.9．ThelastpartshowsChinahasseenresultsfromitseffortsin_________.A．protectingwildanimals B．controllingairpollutionC．developingprotectedareas D．recordingweatherconditions10．Whatisthemainpurposeofthetext?A．Totellpeoplehowtoprotecttheearth.B．Tointroducebiodiversityconservation.C．Tocallforactiononpopulationanddevelopment.D．ToshareChina’sachievementsinbiodiversityconservation.【答案】6．A

7．C

8．A

9．C

10．D【导语】本文主要介绍了中国在生物多样性保护方面取得的成就。6．细节理解题。根据“thefirstnaturereserve(保护区)wassetupin1956,”可知，中国第一个自然保护区成立于1956年。故选A。7．细节理解题。根据表格“lessthan200(1980s)”可知，在20世纪80年代，亚洲象的数量少于200个。故选C。8．细节理解题。根据表格“Crestedibis:about4,400；Hainangibbon:between30and40in5groups；Asianelephant:about300；Giantpanda:1,864”可知，现在朱鹮的数量最多。故选A。9．细节理解题。根据“Theeco-environment；PM2.5dropped36%；Dayswithgoodairqualitygrew11%”可知，最后一部分主要展示了中国在保护区建设方面取得的成果。故选C。10．主旨大意题。根据“Chinahasalwayspaidhighattentiontobiodiversityconservation.Andyearsofeffortshavepaidoff.”可知，本文主要介绍了了中国在生物多样性保护方面取得的成就。故选D。C（2022·广东湛江·校联考二模）TheYangtzeRiveristhelongestriverinChina.Forofyears,alotofpeoplehavemadetheirlivingalongtheriver.Manyofthemarefishermen.However,sinceJanuary1,2020,Chinahasbeguna10-yearban(禁令)onfishinginconservationareas(保护区)alongtheYangtzeRiver.AndfromJanuary1,2021,fishingisnotallowedinallnaturalwaterwaysoflargelakesconnectedtotheYangtzesuchastheDongtingLakeandPoyangLakefor10years.TheYangtzeRiverusedtohavehighbiodiversity(生物多样性).However,humanactivitiessuchasoverfishingandpollutionhavemadefishfewerandfewerintheriver.Inrecentyears,thenumberoffishcaughteveryyearfromtheYangtzehasfallengreatlyfrommorethan420,000tonsinthe1950stolessthan100,000tons.Fishfromtheriverusedtotakeup60%ofthecountry’stotalfishproduction.Butnowthenumberislessthan0.2%.Sothefishingbanisakeymovetoprotecttheriver’sbiodiversity.Thefishingbanwillaffect(影响)about280,000fishermenalongtheriver.Thegovernmenthastakenactiontohelpthosefishermen.Forexample,itprovidesthemwithmoneyandjobtrainingsothattheycanfindnewwaysofliving.YangZhiming,afishermaninHunanProvince,nowmanagesbusinessatalocalmarket.Yangboughtaplaceatthemarketwith20,000yuanfromthelocalgovernmentyearsago.“Now,the10-yearfishingbanhasstarted.Myfamilydon’thavetoworrytoomuchbecausewecandosomebusinessatthemarket,”hesaid.“TheDongtingLakeishometousfishermen.Westopfishingtoprotectourhome.”11．Toknowwhatthefishingbanis,youcanread________.A．Paragraph2 B．Paragraph3 C．Paragraph4 D．Paragraph512．ThewriterexplainedtheproblemoftheYangtzeRiverinParagraph3by________.A．tellingastory B．listingexperts’opinionsC．comparingnumbers D．describingapersonalexperience13．Becauseofthefishingban,________.A．about20,000fishermenareaffectedB．fewpeoplewilllivealongtheYangtzeRiverC．thegovernmenthastakenactiontohelpthefishermenD．fishingalongtheYangtzeRiverisnoallowedforthenext20years14．WhatdoYangZhimingandhisfamilythinkofthefishingban?A．Theysupportit. B．Theythinkit’sunfair.C．Theythinkit’stoostrict. D．Theydon’tcareaboutit.15．Inwhichpartofanewspapercanwefindthepassage?A．Health. B．Education. C．Science. D．Environment.【答案】11．A

12．C

13．C

14．A

15．D【导语】本文是一篇说明文。主要向我们介绍“禁渔令”的相关情况，呼吁人们保护我们的家园。11．段落大意题。根据“However,sinceJanuary1,2020,Chinahasbeguna10-yearban（禁令）onfishinginconservationareas（保护区）alongtheYangtzeRiver.”可知本文第二段介绍禁令的相关内容，故选A。12．段落大意题。根据“frommorethan420,000tonsinthe1950stolessthan100,000tons.Fishfromtheriverusedtotakeup60%ofthecountry’stotalfishproduction.Butnowthenumberislessthan0.2%.”可知，主要是通过比较数字来解释长江的问题，故选C。13．细节理解题。根据“Thegovernmenthastakenactiontohelpthosefishermen.”可知，政府已经采取行动帮助这些渔民。故选C。14．推理判断题。根据“Myfamilydon’thavetoworrytoomuchbecausewecandosomebusinessatthemarket”可知，杨志明和家人不用太担心，因为他们可以在市场上做一些生意，所以他们认为“禁渔令”是好的，故选A。15．推理判断题。本文主要向我们介绍“禁渔令”的相关情况，呼吁人们保护我们的家园，所以推测可以在环境版块看到这篇文章，故选D。D（2022·广东惠州·惠州一中校考二模）Today,robotscanbefoundjustabouteverywhere.Sometimestheysimplymakeourliveseasier,suchasrobotcleanersinhotelsorrobotwaitersinrestaurants.Moreimportantly,wedependonrobotstodothingsthatareeitherunsafeorthatwephysicallycannotdo.Infact,twoofthemostimportantplaceswhererobotsarehelpingpeopleareinouroceansandspace.Oceanscover71percentofourplanet,butwe’veonlyexploredabout5percentofit!Becauseoftheoceans’unpleasantenvironment,it’sdifficultforhumanstostudyitslargeparts,sorobotsareavaluabletool.OneofthefirstunderwaterrobotswasAlvin,whichplunged（下降）toadepthof10.7metersinMay1964.Alvincarriedthreepeoplewhooperateroboticarmstocollectsealivesanddirtsothatscientistscouldstudythem.Sincethen,advancementsintechnologyhavemadeourunderwaterexplorationsevengreater.Atthesametime,inspace,robotsarehelpingusexploreourneighboringplanets.Lastyear,Chang’e5lunarrover（探测器）collectedrocksfromthemoon’ssurfaceandbroughtthembacktoearth.Robotsinspacehaveamuchlongerhistorythanthat.Likemanytechnologicaladvancements,it’seasytoforgetjusthowgreataninfluencerobotics（机器人技术）hashadonourlives.However,withoutrobots,weneverwouldhavediscoveredthewondersinourskiesorlearnedabouttherichbiodiversity（生物多样性）lyingjustunderourfeet.16．Theexamplesthewritershowsatthebeginningofthearticletellus______.A．theimportanceofrobots B．robotsareinterestingC．robotsarenotwidelyused D．wedependonrobotstoomuch17．Theunderlinedword“it”inParagraph2isabout______.A．robots B．ourplanet C．oceans D．thespace18．Accordingtothepassage,Alvinmayhelppeopleto______.A．dropdown10.7metersdeep B．operateroboticarmsC．studythingscollectedfromthesea D．collectlivesanddirtinthesea19．Theword“advancements”inthethirdparagraphmeans______.A．progress B．situation C．danger D．instructions20．Whichcanbethebesttitleforthispassage?A．TheFutureOceans B．ThePowerfulRobotsC．TheProgressofHumans D．TheRiseofPersonalRobots【答案】16．A

17．C

18．D

19．A

20．B【导语】本文是一篇说明文，介绍机器人可以帮助人类做许多工作，用很多不同的方式帮助我们。16．推理判断题。根据“Sometimestheysimplymakeourliveseasier...Moreimportantly,wedependonrobotstodothingsthatareeitherunsafeorthatwephysicallycannotdo.”可知，本段叙述机器人可以让我们的生活更轻松，我们依靠机器人来做一些不安全的事情，或者是我们身体不能做的事情。所以此处是为了说明机器人的重要性，故选A。17．推理判断题。根据“Oceanscover71percentofourplanet,butwe’veonlyexploredabout5percentofit!”可知，海洋覆盖了地球71%的面积，但我们只探索了其中的5%，此处it指的是海洋，故选C。18．细节理解题。根据“Alvincarriedthreepeoplewhooperateroboticarmstocollectsealivesanddirtsothatscientistscouldstudythem.”可知，“阿尔文号”上有三个人，他们操作机械臂收集海洋生物和污垢，以便科学家研究它们。故选D。19．词句猜测题。分析“Alvincarriedthreepeoplewhooperateroboticarmstocollectsealivesanddirtsothatscientistscouldstudythem.Sincethen,advancementsintechnologyhavemadeourunderwaterexplorationsevengreater.”可知，“阿尔文号”上有三个人，他们操作机械臂收集海洋生物和污垢，以便科学家研究它们。从那时起，技术的进步使我们的水下探索更加伟大。此处advancements的意思是“进步”，与progress同义。故选A。20．最佳标题题。本文主要介绍机器人可以帮助人类做许多工作，用很多不同的方式帮助我们。故选B。E（2022·云南红河·统考一模）Humanssharetheearthwithdifferentkindsofwildlife.Humans,plantsandanimalsareconnectedanddependoneachother.Theyareallimportantpartsoftherichbiodiversity(生物多样性)oftheearth.However,manykindsofplantsoranimalsarebecomingendangeredoverthepastyearsbecauseofclimate(气候)changeandhumanactivities.Humansareoneofthemainreasonsforthis.AccordingtoareportbytheUnitedNationsin2019,theworld’spopulationhasdoubled(from3.7to7.6billion)inthepast50years.Humanshaveusedmorethanonethirdoftheworld’slandand75percentoffreshwater.Besides,somehumanactivitieslikecuttingdownforestsandpollutingriversalsodoharmtotheenvironment.Asaresult,therearefewerhabitats(栖息地)andnaturalresources(资源)availableforanimals,aswellasmorepollution.Todealwiththeproblem,manycountrieshavetakenaction.Asoneofthecountrieswiththerichestbiodiversityintheworld,Chinahastakenanactivepartinbiodiversityprotection.TheChinesegovernmenthasdevelopedlawstoprotectwildlifeandsetupabiodiversitymonitoring(监测)network.Ithasalsobuiltnaturereserves(保护区)withnationalparks.FromJanuary1,2019,thefirstlocallawaboutbiodiversityprotectionwasdevelopedinYunnanprovince.YunnanliesinthemountainsareaofSouthwestChinaanditistheareawiththerichestbiodiversityinChinaanditisalsothemostsuccessfulareainChina’sbiodiversityprotection.Forthisreason,in2021,COP15washeldinKunmingandwasagreatsuccess.BiodiversityprotectionrequireseffortsfromthewholeworldandChinaisnowplayingaleadingroleinprotectingbiodiversity,hopingtobuildagreenhomeforbothhumansandnature.21．Whatcanwelearnfromparagraph1aboutthebiodiversityoftheearth?A．Humansliveontheearthandowntheearth.B．Thereisnoconnectionbetweenhumans,plantsandanimals.C．Humans,plantsandanimalsareallimportantpartsofbiodiversity.D．Thebiodiversityoftheearthismainlyinfluencedbyclimatechange.22．Whatcausedthefewerhabitatsandnaturalresourcesforanimals?A．Climatechange. B．Shortforfreshwater.C．Environmentpollution. D．Doubledpopulationandhumanactivities.23．WhatdidChinesegovernmentdotoprotectthebiodiversityoftheearthEXCEPT?A．Developlaws. B．Setupmonitoringnetwork.C．Buildnaturereserves. D．Plantreesandsavefreshwater.24．WhywasYunnanchosentoholdCOP15?A．BecauseitliesinthemountainsareaofsouthwestChina.B．Becauseitdevelopedthefirstlocallawaboutbiodiversityprotection.C．BecauseithastherichestbiodiversityinChinaanddoeswellinbiodiversityprotection.D．Becauseithasbuiltnaturereserveswithnationalpark.25．What’sthebesttitleforthispassage?A．Chinaisworkingontheprotectionofbiodiversity.B．Helpsavetheendangeredanimals.C．China’snaturereserveswithnationalparks.D．Humanactivitiesdoharmtothebiodiversityoftheearth.【答案】21．C

22．D

23．D

24．C

25．A【导语】本文主要描述了野生动物目前的现状，造成这种现状的原因以及倡导人们行动起来改善现状。21．细节理解题。根据“Humans,plantsandanimalsareconnectedanddependoneachother.Theyareallimportantpartsoftherichbiodiversity(生物多样性)oftheearth.”可知，人、植物和动物是相互联系、相互依存的。它们都是地球丰富的生物多样性的重要组成部分。所以从第一段中我们可以知道人类、植物和动物都是生物多样性的重要组成部分。故选C。22．细节理解题。根据“Humanshaveusedmorethanonethirdoftheworld’slandand75percentoffreshwater.Besides,somehumanactivitieslikecuttingdownforestsandpollutingriversalsodoharmtotheenvironment.Asaresult,therearefewerhabitats(栖息地)andnaturalresources(资源)availableforanimals,aswellasmorepollution.”可知，人类已经使用了世界上超过三分之一的土地和75%的淡水；此外，一些人类活动，如砍伐森林和污染河流也对环境造成危害。结果，动物的栖息地和自然资源越来越少，污染也越来越严重。故选D。23．细节理解题。根据“TheChinesegovernmenthasdevelopedlawstoprotectwildlifeandsetupabiodiversitymonitoring(监测)network.Ithasalsobuiltnaturereserves(保护区)withnationalparks.”可知，中国政府已经制定了保护野生动物的法律，并建立了生物多样性监测网络，还建立了自然保护区和国家公园。故选D。24．细节理解题。根据“YunnanliesinthemountainsareaofSouthwestChinaanditistheareawiththerichestbiodiversityinChinaanditisalsothemostsuccessfulareainChina’sbiodiversityprotection.Forthisreason,in2021,COP15washeldinKunmingandwasagreatsuccess.”可知，云南地处中国西南山区，是中国生物多样性最丰富的地区，也是中国生物多样性保护最成功的地区，因此2021年在昆明举办了第十五届缔约方大会。故选C。25．最佳标题题。本文主要描述了野生动物目前的现状，造成这种现状的原因以及倡导人们行动起来改善现状。选项A“中国正在努力保护生物多样性”符合主题，故选A。F（2022·江苏常州·校考一模）Wetlands—lakes,rivers,marshesandcoasts,canmaintainbiodiversity(保护生物多样性),controlfloodsandremovepollutants.Theyarealsohelpfultoriceandfishproduction,transportationandsoon.Theyareimportantandnecessaryfeedingandbreedinggroundsformigratorybirds.Theyarethemostthreatenedecosystem(受到威胁的生态系统).WorldWetlandsDaycamefromtheConventiononWetlands(湿地公约)signedinIran,ChinajoinedtheconventiononJuly31,1992.Bytheendof2019,ourcountryhad57wetlandnaturereserveslistedasmajorwetlandsforprotectionundertheconvention,coveringatotalofnearly7millionhectares.______________________,asChinahaswetlandswith65.9millionhectares,10percentoftheworld’swetlandareas,whichcomesfourthintheworld.ChinaalsohassomeofAsia’smostimportantwetlands,suchasPoyangLakeandAsia’slongestriver,YangtzeRiver.However,aWWFresearchshowedChina’swetlandswereseriouslythreatenedbydegradationbecauseofpollution,climatechangeandover-exploitation.Soourgovernmenthasbeentakingactionstoreturnfarmlandtowetlandandremovesomefishfarms.Itwasreportedthe57keyChinesewetlandsincreasedby2,479hectaresfrom2018to2019.LiYan,anofficialfromtheNationalForestryandGrasslandAdministration,saidatanewsconference,“TheareaofwetlandsinChinahasbecomelargeroverthepastfiveyears,growingby202,600hectaresandmakingagreatcontributiontowaterqualityandenvironmentalprotection.Between2016and2020,Chinacreated201nationalwetlandparks.Chinahad899nationalwetlandparksbytheendof2020,andnearlyhalfofthecountry’swetlandsareprotectedbysomelevelofgovernment.”Chinaiscarryingthroughontheconventionforacontinuousdevelopmentandwillmakecontinuingeffortstoperfectthelawsonwetlandprotection.Severalmajorprojectsonwetlandprotectionwillbecarriedoutinsomemajorareas,suchasYangtzeRiverandtheBeijing-Tianjin-Hebeiprovincecluster.26．Whichofthefollowingisthemostsuitablefortheblank(空格)inParagraph2?A．WorldWetlandsDayiswell-known B．WetlandsinChinaareseriouslythreatenedC．Chinadoesn’thavelargeareasofwetlands D．ProtectionofwetlandsinChinaisveryimportant27．Theunderlinedword“degradation”inParagraph3probablymeans________.A．theprocessofsomethingbeingmadebetterB．theprocessofsomethingbeingmadeworseC．thesituationinwhichsomebodyhaswonalltherespectD．thesituationinwhichsomebodyhaslostalltherespect28．ThewriterlistssomenumbersinParagraph4inorderto________.A．introducehowlargeChina’swetlandsareB．explainhowimportantChina’swetlandsareC．provehowmuchdangerChina’swetlandsarefacingatpresentD．showtheachievementsonwetlandprotectionChinahasreached29．What’sthebesttitleforthepassage?A．WetlandsinChinaareFamous B．ChinaMakesLawsonWetlandProtectionC．China’sWetlandsareinDanger D．ChinaMakesProgressonWetlandProtection【答案】26．D

27．B

28．D

29．D【分析】本文是一篇说明文，向我们介绍了世界湿地日的有关信息，主要介绍中国在湿地保护方面取得的成绩，告诉人们湿地在人们生活中的作用。26．推理判断题。分析“Bytheendof2019,ourcountryhad57wetlandnaturereserveslistedasmajorwetlandsforprotectionundertheconvention,coveringatotalofnearly7millionhectares…asChinahaswetlandswith65.9millionhectares,10percentoftheworld’swetlandareas,whichcomesfourthintheworld.ChinaalsohassomeofAsia’smostimportantwetlands,suchasPoyangLakeandAsia’slongestriver,YangtzeRiver.”可知，本段介绍中国加入湿地公约，介绍了中国在湿地保护方面的努力，选项D“保护湿地在中国是非常重要的”符合语境，故选D。27．词义猜测题。分析“However,aWWFresearchshowedChina’swetlandswereseriouslythreatenedbydegradationbecauseofpollution,climatechangeandover-exploitation.”可知，世界自然基金会的一项研究表明，由于污染、气候变化和过度开发，中国的湿地正受到退化的严重威胁。此处degradation的意思是“退化”，故选B。28．推理判断题。根据“TheareaofwetlandsinChinahasbecomelargeroverthepastfiveyears,growingby202,600hectaresandmakingagreatcontributiontowaterqualityandenvironmentalprotection…andnearlyhalfofthecountry’swetlandsareprotectedbysomelevelofgovernment.”可知，本段列出的各种数据是为了说明中国在湿地保护方面取得的成绩，故选D。29．最佳标题题。本文向我们介绍了世界湿地日的有关信息，主要介绍中国在湿地保护方面取得的成绩，告诉人们湿地在人们生活中的作用。选项D“中国湿地保护取得新进展”符合主题，故选D。G（2022·广东阳江·统考二模）TheChangjiangRiveristhelongestriverinChina.Forthousandsofyears,alotofpeoplehavemadetheirlivingalongtheriver.Manyofthemarefishermen.However,since1stJanuary2020,Chinahasbeguna10-yearban(禁令)onfishinginconservationareas(保护区)alongtheChangjiangRiver.Andfrom1stJanuary2021,fishingisnotallowedinallnaturalwaterwaysoflargelakesconnectedtotheChangjiangsuchastheDongtingLakeandPoyangLakefortenyears.TheChangjiangRiverusedtohavehighbiodiversity(生物多样性).However,humanactivitiessuchasoverfishingandpollutionhavemadefishfewerandfewerintheriver.Inrecentyears,thenumberoffishcaughteveryyearfromtheChangjianghasfallengreatly:frommorethan420,000tonsinthe1950stolessthan100,