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Wateristhe"lifeblood"ofourearth．Likeairandsunshine,itisveryimportant31livingthings．Withoutwater,therecanbe32lifeontheearth．Allanimalsandplantsneedwater.Manalsoneedswater．Weneedwatertodrink,tocookandtoclean33．Iteven34thegreaterpartofourbodies．Waterisalmosteverywhere．Eveninthe35placesoftheworld,thereiswaterintheair．However．wecandrinknotseawaterbutfreshwater．Tomakethingseven36,peopleoften37tokeepthewaterclean．Theythrowrubbishintorivers,lakesorseas．Sonotallthefreshwateris38forustodrink．We'reshort39water．Somethingmustbe40tostopthis．()31．A．byB．toC．ofD．towards()32．A．noneB．notC．muchD．no()33．A．himselfB．ourC．usD．ourselves()34．A．madeofB．makeC．makesupD．madein()35．A．driestB．wetterC．drierD．beautiful()36．A．bestB．worseC．worstD．better()37．A．decideB．tryC．failD．take()38．A．cleanenoughB．enoughcleanC．enoughgoodD．dirtyenough()39．A．forB．inC．atD．of()40．A．doB．didC．doingD．done