7、whetherC.howD.if15.Earthisarockyplanet________liquidwater,whichisnecessaryforlife,canexist.A.asB.whichC.whereD.when16.Isthisschool_______youstudyin?17.Isthistheschool______youstudyin?18.Isthistheschool_______youstudy?19.Isthisschool_______you4study?A.that/which B.where C