Werelyoncoal,oilandfossilfuelsforover80percentofourcurrent(1)能源消耗(B4U7)-asituationwhichshowslittlesignofchangingoverquitealongperiodoftime.Ontopofthis(2)能源需求(B4U7A)isexpectedtoseea(3)直线增长(B4U7A)byalmosthalfoverthenexttwodecades.Undoubtedly,thiswillbecausingan(4)能源危机(B4U7A)andthefearthatour(5)看似充足(B4U7A)energyresourcesarestartingtorunout.Energyshortageswill(6)严重打击(B4U7B)theglobaleconomyandglobalqualityoflife.Thepotentialfor(7)大规模短缺(B4U7B)isveryrealifwerunoutofenergy.However,itisstillpossibletofind(8)可行的替代品(B4U7A).Scientistshaverecentlyturnedtheirattentiontonaturalsourcesof(9)可再生能源(B4U7A):thesun,thesea,thewindandhotsprings.Theyare(10)对环境有利(B4U7A)butsomeofthemhave(11)成本太高的缺陷(B4U7A)tobeaworkablealternativetonon-renewableenergy.Ultimately,(12)无限供应(B4U7A)ofrenewableenergysourcesshouldensurethattheworlddoesnotfallshortofitsenergyneeds.