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1、词义猜测阅读理解专题四:词义猜测题LifeintheClearTransparentanimalsletlightpassthroughtheirbodiesthesamewaylightpassesthroughawindow.Theseanimalstypicallylivebetweenthesurfaceoftheoceanandadepthofabout3,300feet—asfarasmostlightcanreach.Mostofthemareextremelydelicateandcanbedam
2、agedbyasimpletouch.SonkeJohnsen,ascientistinbiology,says,“Theseanimalslivethroughtheirlifealone.Theynevertouchanythingunlessthey'reeatingit,orunlesssomethingiseatingthem.”Andtheyareasclearasglass.Howdoesananimalbecomeseethrough?It'strickierthanyoumightthink.T
3、heobjectsaroundyouarevisiblebecausetheyinteractwithlight.Lighttypicallytravelsinastraightline.Butsomematerialsslowandscatter(散射)light,bouncingitawayfromitsoriginalpath.Othersabsorblight,stoppingitdeadinitstracks.Bothscatteringandabsorptionmakeanobjectlookdiff
4、erentfromotherobjectsaroundit,soyoucanseeiteasily.Butatransparentobjectdoesn'tabsorborscatterlight,atleastnotverymuch.Lightcanpassthroughitwithoutbendingorstopping.Thatmeansatransparentobjectdoesn'tlookverydifferentfromthesurroundingairorwater.Youdon'tseeit—y
5、ouseethethingsbehindit.Tobecometransparent,ananimalneedstokeepitsbodyfromabsorbingorscatteringlight.Livingmaterialscanstoplightbecausetheycontainpigments(色素)thatabsorbspecificcolorsoflight.Butatransparentanimaldoesn'thavepigments,soitstissueswon'tabsorblight.
6、AccordingtoJohnsen,avoidingabsorptionisactuallyeasy.Therealchallengeispreventinglightfromscattering.Animalsarebuiltofmanydifferentmaterials—skin,fat,andmore—andlightmovesthrougheachatadifferentspeed.Everytimelightmovesintoamaterialwithanewspeed,itbendsandscat
7、ters.Transparentanimalsusedifferenttrickstofightscattering.Someanimalsaresimplyverysmallorextremelyflat.Withoutmuchtissuetoscatterlight,itiseasiertobeseethrough.Othersbuildalarge,clearmassofnonlivingjellylike(果冻状的)materialandspreadthemselvesoverit.Largertrans
8、parentanimalshavethebiggestchallenge,becausetheyhavetomakeallthedifferenttissuesintheirbodiesslowdownlightexactlyasmuchaswaterdoes.Theyneedtolookuniform.Buthowthey'redoingitisstillunknown