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1、Unit4 WildlifeprotectionⅠ.阅读Anabsolutedescriptionofthethreathangingovertheworld’smammals,reptiles,amphibians(哺乳、爬行、两栖动物)andotherlifeformshasbeenpublishedbythewell-knownscientificjournalNature.Aspecialanalysiscarriedoutbythejournalindicatesthatanastonishing41%ofallamphibiansonth
2、eplanetnowfaceextinctionwhile26%ofmammalspeciesand13%ofbirdsaresimilarlythreatened.Manyspeciesarealreadycriticallyendangeredandclosetoextinction,includingtheSumatranelephant,theAmurleopardandthemountaingorilla.Butalsoindangerofvanishingfromthewild,itnowappears,areanimalsthatare
3、currentlyratedasmerelybeingendangered.Ineachcase,thefingerofblamepointsdirectlyathumanactivities.Thecontinuingspreadofagricultureisdestroyingmillionsofhectaresofwildhabitats(栖息地)everyyear,leavinganimalswithouthomes,whiletheintroductionofnewly-comespecies,oftenhelpedbyhumans,isa
4、lsodamagingnativepopulations.Atthesametime,pollutionandoverfishingaredestroyingoceanecosystems.“Habitatdestruction,pollutionoroverfishingeitherkillsoffwildcreaturesandplantsorleavesthembadlyweakened,”saidDerekTittensor,anoceanecologistattheWorldConservationMonitoringCenterinCam
5、bridge.“Thetroubleisthatincomingdecades,theadditionalthreatofworseningclimatechangewillbecomemoreandmorecommonandcouldthenkilloffthesesurvivors.”Theproblem,accordingtoNature,isworsenedbecauseofthehugegapsinscientists’knowledgeabouttheplanet’sbiodiversity.Evaluationsofthetotalnu
6、mberofspeciesofanimalsandplantsalivevaryfrom2millionto50million.Inaddition,evaluationsofcurrentratesofspecies’disappearancesvaryfrom500to36,000ayear.“Thatistherealproblemweface,”addedTittensor.“Thescaleofuncertaintyishuge.”6Intheend,however,thedataindicatesthattheworldisheading
7、cruellytowardamassextinction—whichisdefinedasoneinvolvingalossof75%ofspeciesormore.Thiscouldarriveinlessthanahundredyearsorcouldtakeathousand,dependingonextinctionrates.1.What’sthemainideaofthefirsttwoparagraphs?A.Figuresaboutsomewildanimalsareastonishing.B.Natureisthefamousjou
8、rnalaroundtheworld.C.Manyendangeredspeciesareclosetoex
