定语从句在复合句中修饰名词和代词的从句叫做定语从句.被定语从句修饰的名词或代词叫做先行词.引导定语从句的关系代词有who,whose,whom,which,that,as;引导定语从句的关系副词有when,where,why;关系代词在定语从句中做主语,宾语,定语.关系副词在定语从句中做状语.一.由who,引导的定语从句,who在从句中做主语(口语中也可做宾语),修饰表示人的先行词.例如:Thisisthemanwhohelpedme.Doyouknowthecomradewhospokejustnow?Theboywho//whomwesawyesterdayisJohn’sbrother.二.whom引导的定语从句,whom在从句中作宾语,修饰表示人的先行词,口语中可以省略.Thedoctor(whom)youarelookingforisintheroom.Theperson(whom)youjusttalkedtoisMr.Li.=ThepersontowhomyoujusttalkedisMr.Li.(介词后whom不能省略)Thebabieswhomthenursesarelookingforareveryhealthy.(固定短语中的介词一般不省略,介词仍放在动词之后)三.whose引导的定语从句,whose在从句中作定语,修饰表示人或物的先行词.DoyouknowthewomanwhosenameisMary.Passmethedictionarywhosecoverisblack.四.that引导的定语从句,that在从句中做主语或宾语,修饰表示人或物的先行词,作宾语时可省略,不能放在介词后面作宾语.Theletter(that//which)Ireceivedwasfrommyfather.Ican’tfindtheletterthat//whichcamethismorning.Doyoustillrememberthedays(that//which)wespenttogether?Thisisthemanthat//whohelpedme.Thehouse(that//which)weliveinisnotlarge.=Thehouseinwhichweliveisnotlarge.Thedoctor(that//whom//who)youarelookingforisintheroom.五.which引导的定语从句,which在从句中做主语,也可做宾语,或介词的宾语,修饰表示物的先行词.先行词可以是词、短语、句子。用心爱心专心1Thisisthebook(which/that)youwant.Thebuildingwhich//thatstandsneartheriverisourschool.Theroominwhichthereisamachineisaworkshop.(介词后面的which不能省略)Thehouse(which/that)weliveinisnotlarge.Thisisthewatch(which/that)hewaslookingfor.(在含有介词的动词固定词组中,介词只能放在动词之后,不能放在which之前)六、that和which都可以修饰表示物的先行词,但是下列情况只能用that.①.先行词为不定冠词all,few,little,much,everything,nothing等.All(that)youhavetodoistopractiseeveryday.Thereisn’tmuch(that)Icando.②.先行词被序数词或形容词的最高级所修饰时.Thefirstlesson(that)Ilearnedwillneverbeforgotten.Thisisthebestfilm(that)Ihaveeverseen.③.先行词被all,any,every,few,little,no,some等不定代词修饰时.Ihavereadallthebooks(that)yougaveme.④.先行词被theonly,thevery,thelast,thesame等修饰时.ThewhitefloweristheonlyonethatIreallylike.ThisistheverybookthatIwanttoread.ThisisthesamebookthatIwanttoread.(同一本书)----ThisisthesamebookasIwanttoread.⑤.当主句以who或which开头的特殊疑问句时,定语从句that引导.Whoisthemanthatisstandingthere?Whichofusthatknowssomethingaboutphysicsdoesn’tknowthis?⑥先行词既有人又有物时。Wetalkedaboutthepersonsandthingsthatwecouldremember.⑦time做先行词，前面如果有序数词或last来修饰时，定语从句用that来引导或省略；如果没有序数词或last来修饰时，既可用when也可用that来引导。Thisisthelasttime(that)Ishallgiveyoualesson.Thefirsttime(that)Isawhimwasin1972.It’stime(that)wegotup.七、as引导的定语从句，as用作关系代词和关系副词引导限定性定语从句，在从句中作主语、定语、表语、或状语，常用心爱心专心2与thesame…as;such…as,so…as,as…as连用。Ilikethesamebookasyoudo.Iwanttohavesuchadictionaryashehas.Ishalldoitinthesamewayasyoudid.Heisthesameageasyou(are).Hewillgiveyousuchinformationaswillhelpyou.Suchstudentsasyouhavementionedshouldbecriticized.=Studentssuchasyouhavementionedshouldbecriticized.在thesame…后也可用that引导定语从句，但意义有所不同：that引出的定语从句，指的是与先行词同一事物；而as引出的定语从句是与先...
