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1、贵州绥阳县2017高考英语阅读理解一轮专题选练（三）阅读理解。阅读下列短文,从给的四个选项(A、B、C和D)中,选出最佳选项。 Nowscientistsbelievethatglobalwarmingaffectshibernatinganimals,causingthemtowakeupearlier.Whilethismayseemalittleconcern,itisinfactasignificantenvironmentalproblem.Theshortenedhibernationperiodcouldactuallyleadtosignif
2、icantdeclinesinthepopulationofseveralspecies.SomeofthefirstconcreteevidenceofthephenomenoncamefromColorado,whereresearchersattheRockyMountainBiologicallabhavebeenobservingmarmot(旱獭)hibernationbehaviorsincethe1970s.Intheearlydaysoftheirstudies,marmotsgenerallyhibernatedseveralweeksin
3、tothemonthofMay.Nowadays,however,temperaturesintheareahaverisenby2.5degreesFahrenheit,andthemarmotswakeupaboutamonthearlier.Atleastthemarmotsarestillhibernating.Severalotheranimalshavenotbeenhibernatingatallrecently.BrownbearsintheSpanishCantabrianMountainsdidnothibernatelastyear.In
4、partsoftheUnitedStates,chipmunks(花鼠)alsoskippedthehibernationperiod.Thebearsseemtohavesurvivedwithoutlosingmanyindividuals.Thechipmunks,however,werenotsolucky.Manyoftheanimalsdiedofstarvationduringthewinter.Theproblemwithanimalswakingupearly,orskippinghibernationaltogether,lieswitht
5、hecreatures’metabolism(新陈代谢).Whentheanimalshibernate,theirmetabolismdropssignificantly.Theanimals’heartrateslows,andtheyrequireverylittleenergytolive.Whentheanimalsawakefromtheirwinterslumber,theirmetabolismreturnstonormal.Butwhiletheirmetabolismmaybeasactiveasitwasbeforehibernation
6、,foodsourcesaren’tasavailableastheywerebefore.Amarmotmaywakeupwhentemperaturesgetwarmer,thinkingit’sspring,butplantswillnothavegottheamountofsuntheyneedtosignaltheirspringperiodofgrowth.Sountiltheplantsgrow,themarmotshavenoreliablefoodsource.Manyscientistsbelievetheproblemwillcontin
7、uetogetworse.Inadditiontochangesinhibernationpatterns,somebelievethatotheranimalswillalsobegintochangetheirmigrationpatternsorbegintogivebirthearlier.Formanybiologists,that’sascaryprospect.TerryRoot,ananimalexpertatStanfordUniversity,said,“Idothinkwhatwewillbefacingisthe8extinctiono
8、fmanyspecies.”【文章大意
