搜索
第九单元语法知识（定语从句）定语从句：在复合从句中作定语（解释，定语：起修饰和限制作用的语言单位，由形容词充当），修饰主句中的某一名词或代词的从句叫定语从句。被定语从句所修饰的词叫先行词，定语从句总是放在先行词之后。引导定语从句的词叫关系代词that,which,who,whom(宾格），whose（所有格）或关系副词（where,when,why).定语从句在复合句中对先行词起着修饰，限定作用，在句中充当定语的功能。关系代词和关系副词放在先行词与定语从句之间，即起连接作用，又充当从句的重要成分。当关系代词在定语从句中作宾语时，关系代词可省略，而关系代词在定语从句中作主语或定语时则不能省略。注意：关系代词that即可指人，也可指物，指物时可与which互换，指人时可与who或whom互换,但指人时多用who或whom1、that(指人或物）在定语从句中做主语或宾语，作宾语时可省略eg:Ilikemoviesthat/whichmakemelaugh.Thepeoplewho/thatcametovisitthecityareallhere.Whereisthemanthat/whomIsawthismorning.2、which（指物,不能指人）在定语从句中做主语或宾语，作宾语时可省略eg:Footballisagamewhich/thatislikedbymostboys.Thisisthepenwhich/thatheboughtyesterday.Ipreferbookswhich/thatgivemesomethingtothinkabout.3.who(指人，不能指物）在定语从句中做主语eg:Theboyswho/thatareplayingfootballarefromClassone.Iwillinvitesomeonewholikesme.4.whom(指人，不能指物）在定语从句中只能做宾语，其前没有介词时，可用who/whom代替，也可省略eg:Mr.Liuisthepersonwhom/thatyoutalkedabout.Heisthemanwhom/thatyouwouldliketosee.5.whose（指人或物）在定语从句中作定语，可与ofwhich互换eg:Isthereanyoneinyourclasswhose/ofwhichmotherisateacher?Hehasafriendwhose/ofwhichfatherisadoctor.Doyoulikethebookwhose/ofwhichcolorisgreen?6.where(指地点）可与inwhich互换,在定语从句中作地点状语，用来表示地点的定语从句eg:Shanghaiisthecitywhere/inwhichIwasborn.7.when(指时间）可与onwhich互换,在定语从句中作时间状语，用来表示时间的定语从句eg:Istillrememberthedaywhen/onwhichIfirstcametotheschool.8.why(指原因）可与forwhich互换,在定语从句中作原因状语，用来表示原因的定语从句eg:Pleasetellmethereasonwhy/forwhichyoumissedtheplane.一、只用that引导的定语从句，不用which,who,whom的情况有：1）当先新词为anything,nothing,something,everything等指物的不定代词和all,much等时eg:Weshoulddoeverythingthatisusefultothepeople.2)先行词被all,every,no,some,any,little,much,few,oneof,theonly,thesame,thevery,thelast,just等词修饰时；eg:Maryistheonlyonethatwantstobeateacher.3)当先行词被形容词最高级修饰时；eg:ThisisthebeststorythatIhaveread.4)当先行词被序数词修饰时；eg:HeisthefirstpersonthatIwanttosee.5)当先行词同时含有人和物时；eg:Doyouknowthethingsandpersonsthattheyaretalkingabout?6)当主句中已有疑问词who或which时；eg:Whichisthebikethatyoubought?Whoisthestudentthatwaspraisedatthemeeting?7)有两个定语从句，为了避免重复，其中一个关系代词已用which,另一个则用that;eg:Hebuiltupafactorywhichproducedthingsthathadneverbeenseenbefore.8)在therebe句型中；eg:Istherethebookthatyouborrowedinthelibrary?二、只用which引导的定语从句，不用that的情况用：1）关系代词前有介词时（of,for,with,in,on....)eg:IwantfindthepenwithwhichIwrotetheletter.（我想找到我用来写信的钢笔）2）当先行词为that或those时；3)在非限定性定语从句中（解释，非限定性定语从句：即通常用逗号隔开，若去掉从句，整个句子仍然表达完整意义的定语从句）eg:Football,whichisaveryinterestinggame,isplayedallovertheworld.三、只用who引导的定语从句，不用that的情况有：1)当先行词为everyone,someone,noone,nobody,everybody,somebody等表示人的不定代词时eg:Isthereanyonewhocananswerthequestion?2)当先行词为those时eg:Thosewhogototheparkstayhere.