掌握定语从句的用法必须突破以下六道难关•一.选准关系代词和关系副词在定语从句中,关系代词或关系副词都代替先行词在从句中充当一定的成分,如果该从句中缺少主语、表语、宾语或定语,就要用关系代词来连接从句;如果从句中缺少状语,就得用关系副词来连接从句。例如:•(1)Istillrememberthedayswhich/thatwespenttogether.(2)Istillrememberthedayswhenweworkedtogether.•二.了解仅用that引导限制性定语从句的几种情况that在限制性定语从句中既可指人又可指事或物。在下列情况下,只能用that来引导定语从句:•1.先行词是all,much,few,little,everything,anything,nothing等不定代词时。例如:Isthereanythingthatyouwanttobuy?•2.先行词被all,few,little,much,every,some,no等词修饰或被theonly,thevery,thesame,thelast等限定词修饰时。例如:TheseareallthepicturesthatIhaveseen.Thisistheverydictionarythatisofgreathelp.•3.先行词既指人又指物时。例如:Myfatherandhisteachertalkedalotaboutthethingsandthepersonsthattheycouldremember.•4.关系代词在定语从句中作表语时。例如:Ourschoolisnottheonethatitusedtobe.•5.先行词被形容词最高级或序数词修饰时。例如:ThisisthebestEnglishfilmthatIhaveeverseen.ThefirstEnglishnovelthatIreadwasATaleofTwoCities.•6.主句是who或which引导的特殊问句时。例如:Whoisthegirlthatisstandingunderthetree?WhichisthemachinethatweusedlastSunday?•三.把握“介词+关系代词”结构中介词的选用介词的选择与主句中先行词的搭配密切相关。例如:That”sthereasonforwhichhewaslateforschool.ThisisthebookonwhichIspent8yuan.•注意:1.定语从句中谓语动词是含有介词的动词短语时,介词应放在动词之后,不能拆开放在关系代词前。例如:Thisisthekeywhichyouarelookingfor.•Thisisthebabywhomyouwilllookafter.2.该结构中,关系代词指人时用whom,指物时用which.•四.弄清as和which引导的非限制性定语从句指代整体时的区别1.位置上的区别:as引导的非限制性定语从句的位置比较灵活,可以放在主句前,也可以放在主句后,还可插在主句的中间;而which引导的非限制性定语从句只能放在主句之后。例如:•Asisknowntousall,theearthturnsaroundthesun.Theearth,asisknowntousall,turnsaroundthesun.Theearthturnsaroundthesun,asisknowntousall.Theearthturnsaroundthesun,whichourparentsoncetolduswhenwewereveryyoung.•2.词义与联系上的区别:as引导的非限制性定语从句与主句之间有着较为密切的上下文联系,as本身含有“正如”之意;而which引导的非限制性定语从句与主句之间在逻辑意义上近似并列句,which本身表示“这”或“这一点”之意。例如:••Lighttravelsfasterthansound,asweallknow.Jackcamelateforschool,whichmadehisteacherangry.•五.注意定语从句的主谓一致性关系代词在定语从句中作主语时,从句的谓语必须与先行词保持人称和数的一致。例如:•TomisoneoftheboyswhoarefromtheUSA.TomistheonlyoneofthetheboyswhoisfromtheUSA.•六.保持主句的完整性并避免从句成分的重叠1.在定语从句中,不管出现任何情况,主句的结构必须完整,即主句必须有主语和谓语,缺一不可,否则,整个主从复合句就无法成立。试比较:•(1)Isthisfactory_____________wevisitedlastweek?D•(2)Isthisthefactory____________wevisitedlastweek?AA.whichB.whereC.whatD.theone•分析:第一题缺少表语,只有填D项才能保持主句的完整性,而其他的选项均为干扰项。第二题主句本身完整,应填的关系代词在从句中作visited的宾语,故应选A项。•2.从定语从句中,关系代词或关系副词已经代替先行词独立地或与相应的介词一起在定语从句中充当了一定的成分,因此在定语从句中就不能再出现与关系代(副)词重叠的成分。例如:•错句:IsthisthetrainthattheytookitlastSunday?分析:该题中that已经代替先行词thetrain在定语从句中充当及物动词took的宾语,故重叠出现的宾语it必须删去。•总之,只要突破了以上六道难关,定语从句中的难题便会迎刃而解