主题：水循环题型：流程图Thediagrambelowshowsthewatercycle,whichisthecontinuousmovementofwateron,aboveandbelowthesurfaceoftheEarth.满分范文：Thepictureillustratesthewayinwhichwaterpassesfromoceantoairtolandduringthenaturalprocessknownasthewatercycle.Threemainstagesareshownonthediagram.Oceanwaterevaporates,fallsasrain,andeventuallyrunsbackintotheoceansagain.Beginningattheevaporationstage,wecanseethat80%ofwatervapourintheaircomesfromtheoceans.Heatfromthesuncauseswatertoevaporate,andwatervapourcondensestoformclouds.Atthesecondstage,labelled‘precipitation’onthediagram,waterfallsasrainorsnow.Atthethirdstageinthecycle,rainwatermaytakevariouspaths.Someofitmayfallintolakesorreturntotheoceansvia‘surfacerunoff’.Otherwise,rainwatermayfilterthroughtheground,reachingtheimperviouslayeroftheearth.Saltwaterintrusionisshowntotakeplacejustbeforegroundwaterpassesintotheoceanstocompletethecycle.
