一、定语从句的有关概念：在复合句中，修饰某一名词或代词的从句叫做定语从句。如：1)Themanwho/thatlivesnexttousisapoliceman.2)YoumustdoeverythingthatIdo.在上面两句中的man和everything是定语从句所修饰的词，叫先行词。定语从句放在先行词后面。引导定语从句的关系词有关系代词：that,which,who(宾格whom,所有格whose)和关系副词where,when.关系词（关系代词或关系副词）放在先行词和定语从句之间，起联系作用，同时又作定语从句的一个成分。也就是说关系词有两个作用：1.引导定语从句。2.代替先行词在其引导的定语从句中充当一定的句子成分。二、有关系代词引导的定语从句：关系代词例句that在从句中作主语或宾语(作宾语时that可省略)指物1.Aplaneisamachinethatcanfly.(作主语)2.Thenoodles（that）Icookedweredelicious.(作宾语)指人1.Whoisthemanthatisreadingthebookoverthere?(作主语)2.Thegirl(that)wesayyesterdaywasJim’ssister.(作宾语)Which在从句中作主语或宾语(作宾语时可省略)指物1.ThesilkwhichisproducedinHangzhousellswell.(作主语)2.Thesongs（which）LiuDehuasangwereverypopular.(作宾语)Who,whom在从句中分别作主语和宾语（如果介词放在从句后面，则whom可以省略）指人1.TheforeignerwhovisitedourclassyesterdayisfromCanada.(作主语)2.TheboywhobreakthewindowiscalledRoy.(作主语)3.ThepersontowhomyoujusttalkedisMrLi.(作宾语)4.MrsWhiteisthepersontowhomyoushouldwrite.(作宾语)关于that;which用法请注意：①先行词之前有all,every,any,no,little,much,few等词修饰时，或者其本身为all,everyone,everybody,everything,nobody,nothing,anything,anyone,anybody等不定代词，代替物时，定语从句that用引导。注：something后一般用which。Isthereanythingthatyouwanttoexplain?Everyonethatheardhersadstorywasmovedtotears.In1898theydeclared（声明）thattheybelievedtherewassomethinginnaturewhichgaveoutradiation.(辐射)②先行词前有形容词最高级、序数词或only,very,none,,thefirst,thelast,thesame表示“惟一”观念的形容词等修饰时，定语从句用that引导。That可指人，也可指物。ThisistheonlyreasonthatIcansay.Thisisthefirststepthatcanbetaken.Itisthebestonethatyoumaychoose.③当主句中有who,which时，而定语从句中也要用到who或which时，为了避免who…who,which…which等重叠，定语从句用that引导。Whoisthemanthatisstandingbythedoor?Whichofthetwocowsthatyoukeepproducesmoremilk?④先行词为人和物作并列成分时，定语从句用that引导。Johnandhisdogthatwerehereamomentagodisappearnow.⑤不论人或物在定语从句中作表语时，用that引导定语从句，而that通常省掉。Heisnolongerthemanthathewas.⑥先行词是一个短语或者是一个句子时，关系代词用which(大多数情况是非限制性定语从句)Hemissedthetrain,whichannoyed(使。。。恼火)himverymuch.注意事项：1.一般说来，除了用定语从句解释名词或泛指外，先行词前应有定冠词the。2.在限制性定语从句中which,whom,that充当宾语时，可以省略。而在非限制性定语从句中whom,who,which不能省略。3.“oneof＋可数名词复数”引导的定语从句中,谓语动词应用复数；而“oneof＋可数名词复数”前有the，only或theonly修饰，定语从句中的谓语动词用单数。Heisoneofthestudentswhostudyveryhardatschool.Heisthe(only/theonly)oneofthestudentswhostudiesveryhardatschool.
