剑桥雅思IELTS第套Test阅读真题及答案详解-豆柴文库

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剑7Test1阅读Passage1真题及解析
READINGPASSAGE1Youshouldspendabout20minutesonQuestions1-13,whicharebasedonReadingPassage1onthefollowingpages.
Let’sGoBats

ABatshaveaproblem:howtofindtheirwayaroundinthedark.Theyhuntatnight,andcannotuselighttohelpthemfindpreyandavoidobstacles.Youmightsaythatthisisaproblemoftheirownmaking,onethattheycouldavoidsimplybychangingtheirhabitsandhuntingbyday.Butthedaytimeeconomyisalreadyheavilyexploitedbyothercreaturessuchasbirds.③Giventhatthereisalivingtobemadeatnight,andgiventhatalternativedaytimetradesarethoroughlyoccupied,naturalselectionhasfavouredbatsthatmakeagoofthenight-huntingtrade.Itisprobablethatthenocturnaltradesgowaybackintheancestryofallmammals.②Inthetimewhenthedinosaursdominatedthedaytimeeconomy,ourmammalianancestorsprobablyonlymanagedtosurviveatallbecausetheyfoundwaysofscrapingalivingatnight.Onlyafterthemysteriousmassextinctionofthedinosaursabout65millionyearsagowereourancestorsabletoemergeintothedaylightinanysubstantialnumbers.BBatshaveanengineeringproblem:howtofindtheirwayandfindtheirpreyintheabsenceoflight.①Batsarenottheonlycreaturestofacethisdifficultytoday.Obviouslythenight-flyinginsectsthattheypreyonmustfindtheirwayaboutsomehow.Deep-seafishandwhaleshavelittleornolightbydayorbynight.Fishanddolphinsthatliveinextremelymuddywatercannotseebecause,althoughthereislight,itisobstructedandscatteredbythedirtinthewater.Plentyofothermodernanimalsmaketheirlivinginconditionswhereseeingisdifficultorimpossible.CGiventhequestionsofhowtomanoeuvreinthedark,whatsolutionsmightanengineerconsider?Thefirstonethatmightoccurtohimistomanufacturelight,tousealanternorasearchlight.Firefliesandsomefish(usuallywiththehelpofbacteria)havethepowertomanufacturetheirownlight,buttheprocessseemstoconsumealargeamountofenergy.Firefliesusetheirlightforattractingmates.Thisdoesntrequireaprohibitive（费用，价格等）过高的amountofenergy:amale'stinypinprickoflightcanbeseenbyafemalefromsomedistanceonadarknight,sincehereyesareexposeddirectlytothelightsourceitself.However,usinglighttofindone