必修3unit4-grammar主语从句.ppt

Welcome Howdinosaursdisappearedisnotonlyaquestionwhichinterestsbiologistsandgeologists Itisafavoritetopicfordiscussionforphysicistsandastronomers Theywouldliketoknowwhydinosaursbecameextinctbecausethismayhelpthemfindwaystosolvetheproblemofglobalwarming Somescientistsbelievethattheearthslowlybecamehotanddrydozensofmillionsofyearsago Howtheclimatechangedisuncertain butwaterandfoodsupplydecreasedandsothedinosaursgraduallydiedout However themammalssurvived Otherscientistsbelievethatcometcrashedintotheearthlongagoandcausedthedisappearance Asaresultofthisevent agreatdustcloudformedintheskyblockingoutthesunlight Withoutsunlight mostplantssoondiedandsomanydinosaurspeciesbecameextinct Sincetheiceage theclimateoftheearthhasnotchangedverymuch However whethertheclimatewillchangeagainisaconcernforeverybodyonearth 1 主语从句 从句在句中充当主语成分 1 Howdinosaursdisappearedisnotonlyaquestionwhichinterestsbiologistsandgeologists onlyaquestionwhichinterestsbiologistsandgeologists Howtheclimatechangedisuncertain butwaterandfoodsupplydecreasedandsothedinosaursgraduallydiedout 3 Whethertheclimatewillchangeagainisconcernforeverybodyonearth 1 引导主语从句的连接词有三类 1 连词that whether whethertheclimatewillchangeagainisaconcernforeverybodyonearth Whetherhe llcomehereisn tclear Thatpricewillgoupiscertain Whatshedidisnotyetknown Whowillwritethepoemhasnotbeendecidedyet Whateverhedidisright 2 连接代词who whom whose what which whoever whatever whichever等 3 连接副词where when how why等 Howthishappenedisnotcleartoanyone Whenhewillbebackdependsontheweather Howthepyramidswerebuiltisstillamystery It 作形式主语 为了避免主语冗长 句子头重脚轻 经常用it作形式主语 主语从句放在后面作真正的主语 1 Thatweshallbelateiscertain It scertainthatweshallbelate 2 Thattheearthisroundisknowntoall 3 Thatyoumissedthechanceisapity Itisapitythatyoumissedthechance It sknowntoallthattheearthisround 4 ThatChinahaswon51goldmedalsinthe29thOlympicsisreported ItisreportedthatChinahaswon51goldmedalsinthe29thOlympics 注意 Whatyouleftareonlyseveraloldbooks Whatyousaidisofgreatimportance 1 if 不能引导主语从句 应有 whether 引导 3 主语从句的 that 一般不能省 4 what 引导主语从句时 谓语动词 1 常与其后的名词作表语一致2 根据句子的语境而定 4 主语从句需注意的问题 2 主语从句中用陈述语序 Itisdoubtfulifhehasreceivedyourletter 1 Whereshallwespendtheholidayisn tdecided 2 Youhavemadeamistakeisafact 3 Thatiscertainthatwecanwin 4 Nomatterwholeavestheroomlastoughttoturnoffthelights 5 Ifthepolicemenwillcomeisnotcertain weshall Thatyouhave Itis Whoever whether 改错练习 hemadeanimportantspeechatthemeetingwastrue A ThatB WhyC WhatD How 2 we llgocampingtomorrowdependsontheweather AIfBWhetherCThatDWhere 3 isknowntousallisthatAmericaisadevelopedcountry theFirstWorld Which belongtob As belongedtoc What belongingtod It belongingto 4 It sknowntousall aformofenergy A waterisB thatwaterisC iswaterD tha