Earthisanoceanplanet.Aboutthreebilionyearsago,lifeonourplanetbeganinthedeepblueseas.Ninety-ninepercentofthelivingspaceonearthisintheoceans.Sowaterisveryimportantforus.Thewaterisbeingwidelyusedforelectricity 　　agriculture,homeuse,industry,transport,entertain---ment,andsoon.Butthemajorityofpeoplehavenotrealizedthisproblem.SincechangesinsalinityandtemperatureaffectWater'sdensity,thewaterintheoceanisalwaysmoving.Densewatersinksandlessdensewaterispushedtothesurface,Thiscirculationaddsenergytothemarineecosystemsandmovesnutrientsaround.Isn'titamazingthatasinglesubstancecanbesoimportanttooutplanetandeventhewholeuniverse?Water,whichseemssosimpleandcommon,iswhatmakeslifepossible.Ofalltheresourcesonearth--oils,gas,goldandsoon--nothingisaspreciousasadropofrain.Learningaboutthepropertiesofwaterhelpsusunderstandlifeonourplanet.Themostimportantthingwecanlearnaboutwater,however,isthatprotectitanduseitwisely.Ourfuturedependsonit. 　　给你一篇短文,你自己挑几句吧,如果觉得还行就支持一下,谢谢