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.

Passage9<br/><spanstyle="display:block;text-align:center;">EvolutionoftheShark</span>Theshark,whateverelseitmightbe,isalmostuniquelysuccessful.Accordingtofossilevidence,theearliestshark-likecreaturesprowledtheworld’soceans450millionyearsago—longbeforetheageofdinosaurs.Comparedtothis,man’sspanofacoupleofmillionyearsisamereflashofatigershark’stail.<br/>Evolutionisthegrindinglyslowprocesswhichrewardssuccessby“survivalofthefittest”.Organismsbestsuitedtoexploittheirenvironmentsurvivetobreed,producingmorelikethemselves.Thoselesssuitedtotheirsurroundingsfailtoprosperandsimplydieout.Ifanenvironmentchanges,whichmaymeanchangesinpredators*orfoodsupply,aswellasphysicalsurroundings,aspeciesmayneedtoadaptifitistosurvive.<br/>Whathappensinpracticeisthatoneormoreofthemyriadtinydifferencesthatoccurnaturallyinapopulationbecomeanadvantageordisadvantage.Ifthecharacteristicisanasset,thecreaturepossessingitismorelikelytosurviveandpassitontothenextgeneration.Ifitisnot,theindividual,andthecharacteristic,aremorelikelytodieout.Humans,forinstance,althoughallpartofthesamespecies,comeinmanyshapesandsizes.Althoughmodemman’scapacitytochangehisenvironmenthasreducedhisneedtoadapttoit,someofthesecouldbecomemoreorlessadvantageousifoursurroundingsweretochange.<br/>Althoughtheshark’senvironment,thesea,hasprobablybeenmoreconstantthantheone-thirdoftheglobethatisland,sharks,too,haveundergoneinnumerablechangesoverthemillennia.AsNatureexperimentedtofindherperfectfish,thereweremanysuccessesbutprobablymanymoredeadends.Someofthesearepreservedinlayersofancientrock,the“fossilrecord”,fromwherepaleontologists**laterunearththem.<br/>*predator：捕食其他动物为生的动物<br/>**paleontologist：古动物学家<br/><spanstyle="display:block;text-align:right;">(2005年5月试题)</span>