下学期unit1project高一英语课件
日期：2010-04-14 04:18
forexample，allsharksmustswiminordertoavoidsinkingtowardtheoceanfloorThesharkhassensesspeciallyadaptedfortheanimalslifeunderwaterSmellisasharksmostacutesenseApproximately70percentofthesharksbrainisusedforsmellingfunctionsExperimentshaveshownthatsharkscandetectpreysolelybysmell，andthehungriertheshark，canliestillandfantheirgillstobringoxygen-richwateracrosstheslitsBecausetheylackaswimbladder，inordertokeepwatermovingpasttheirgillslitsbutthisisnottrueofallspeciesNursesharks，Unit1ProjectProducingaTVshowSeaweedscanproducevariouschemicalsthathelpkeeptheseawatercleanSharkattacksSharkSpeciesWhalesharkBaskingsharkGreatwhitesharkTigersharkBluesharkWhatareSharks?SharksarefishthathavebeenaroundsincethedinosaursMalesarecalled“Bulls”Femalesarecalled"Cows"BabySharksarecalled"Pups”OthersharkfactsSharkshavefivetosevengillslitsManysharksmustkeepmovinginordertobreathethatis，thelessstimulantneededtoelicitareactionSharksaresensitivetolightandcandetectcertainobjects，
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