2009年12月20日大学英语四级(cet-4)模拟试卷7

《2009年12月20日大学英语四级(cet-4)模拟试卷7》由会员上传分享，免费在线阅读，更多相关内容在工程资料-天天文库。

1、2009年12月20日大学英语四级(CET-4)模拟试卷7PartⅠWritingDirections:forthispart,youareallowedthirtyminutestowriteacompositiononthetopic:AreFamiliesDemandingTooMuchfromTheirChildren?Youshouldwriteatleast120wordsfollowingtheoutlinegivenbelowinChinese:AreFamiliesDemandingTooMuch

2、fromTheirChildren?1.有人认为知识产权保护很重要2.有人认为盗版更实际3.你的看法或：1.越来越多的人关注动物福利2.也带来一些矛盾3.你的看法PartⅡReadingComprehension(SkimmingandScanning)Directions:Inthispart,youwillhave15minutestogooverthepassagequickly.Y(forYES)ifthestatementagreeswiththeinformationgiveninthepassage;

3、N(forNO)ifthestatementcontradictstheinformationgiveninthepassage;NG(forNOTGIVEN)iftheinformationisnotgiveninthepassage.Forquestions8-10,completethesentenceswithinformationgiveninthepassage.Nuclearpowerplantsprovideabout17percentoftheworld'selectricity.Somecoun

4、triesdependmoreonnuclearpowerforelectricitythanothers.InFrance,forinstance,about75percentoftheelectricityisgeneratedfromnuclearpower,accordingtotheInternationalAtomicEnergyAgency.IntheUnitedStates,nuclearpowersuppliesabout15percentoftheelectricityoverall,butso

5、mestatesgetmorepowerfromnuclearplantsthanothers.Therearemorethan400nuclearpowerplantsaroundtheworld,withmorethan100intheUnitedStates.Haveyoueverwonderedhowanuclearpowerplantworksorhowsafenuclearpoweris?Inthisarticle,wewillexaminehowanuclearreactorandapowerplan

6、twork.UraniumUraniumisafairlycommonelementonEarth,whichwastakenintotheplanetduringtheplanet'sformation.Uraniumisoriginallyformedinstars.Oldstarsexploded,andthedustfromtheseshatteredstarsaggregatedtogethertoformourplanet.Uranium-238(U-238)hasanextremelylonglife

7、(4.5billionyears),andthereforeisstillpresentinfairlylargequantities.U-238makesup99percentoftheuraniumontheplanet.U-235makesupabout0.7percentoftheremaininguraniumfoundnaturally,whileU-234isevenrarerandisformedbythedecayofU-238.NuclearFission(裂变)Anuclearfissionh

8、appenswhenauranium-235nucleuswithaneutroncapturesanotherneutron.Thenucleusthensplitsintotwolighteratomsandthrowsofftwoorthreenewneutrons(thenumberofejectedneutronsdependsonhowtheU-