根据短文填空
Waterisall__us.Waterisinthe__.Waterisinthelakesandrivers.Waterisalsointhe__.Thereismorewaterthanlandonthe___.Alllivingthingsmusthaveit.Wemustittoo.Wecannotlivewithoutwater.Sometimes,wedonothaveallthewaterthatweneed.Thelandwill__upwithoutwater.Sometimestherecan__toomuchwaterintheland.Ifit__veryveryhard,therainwaterwillrundownthehills.Ittakessomeofthe__withitwhenitrunsdownthehills.Itiscalled"erosion"whenthewatertakestheland__.