Revision：定语从句的功用：相当于一个形容词，修饰一个名词或代词（即先行词）。常紧跟在先行词后，作定语用。如：Idon’tlikethemanwhowearsabeard.宾语从句的功用：相当于一个名词，作宾语表语从句的功用：如：Idon’tknowwhereIcangotsomuchmoney.Itdependsonwhetherwehaveenoughmoney.Iamsurethathewillcomethisafternoon.相当于一个名词，作连系动词如:be,look,taste,seem等后的表语。一、表语从句的定义：表语从句在复合句中作主句的表语。表语从句和主语指同一内容，它对主语进行解释、说明，使主语的内容具体化。二、表语从句的表现形式1.由从属连词引导。如：“that”,“whether”Thequestioniswhetherweshouldaskthemforhelp.Thetroubleisthathehasneverdonetheworkbefore.2.由连接代词引导。如：“what”“who”“whom”“whose”“which”Guilinisnotwhatitusedtobe.Whatshewantstoknowiswhichdresssheshouldbuy.3.由连接副词引导。如：“when”“why”“where”“how”“because”ThatiswhereLuXunusedtolive.Thatiswhyhedidn’tpasstheexam.4.另可由asif,asthough引导。如：Itlooksasifitweregoingtorain.一些引导词的用法（一）that在表语从句中,又。Thefactisthathehasn’tyetrecoverfromillness.Thereasonwhyhehastogoisthathismotherisillinbed.既不充当成分没有意义比较that在定语从句中的用法。TherearesomefilmsthatI’dliketosee.SheistheonlystudentthatknowsFrench.结论:that在引导定语从句时,指事物,也可指人,在从句中作主语或宾语,作宾语时常可省略。一些引导词的用法（二）What在表语从句中充当表示.1.Thequestioniswhatcausedtheaccident.2.Thatmountainisnotwhatitusedtobe.3.Whathetoldyouwaswhathadbeendiscussedatthemeeting.句子成分什么，什么样子，什么样子人或事另：what不引导定语从句一些引导词的用法（三）•whether在表语从句中表,但不充当句子的成分。if引导表语从句.如:Whatthedoctorreallydoubtsiswhethermymotherwillrecoverfromtheseriousdiseasesoon“是否”不能1.LiLeiisnowinanewjacket.HelooksasifhewereanAmericanboy.2.Thegirlisgivingusavividdescriptionofthemoon.Itseemsasifshehadbeentothemoonmanytimes.一些引导词的用法（四）由asif引导表语从句时要注意语态.若从句表示与现在事实相反,谓动用,与过去事实相反用一般过去式（be用were）had+p.p.
