定语从句概念：担任定语功能的句子称为定语从句。构成：定语从句是由先行词、关系词两个主要部分构成的。被定语从句修饰的词被称为先行词，引导定语从句的词被称为关系词，关系词根据其在定语从句中的功能可分为关系代词和关系副词。常用的关系代词有：that,which,who,whom,whose,as常用的关系副词：where,when,why一关系代词的用法1who/whom二者都用于指人who可作主语、宾语whom只可作宾语Inthisearthquake,thenumberofpeoplewholosthomesreachedasmanyas250,000.Ihavemanyfriendswho/whomIamgoingtosendpostcards.2whose既可指人，也可指物。作定语。Youaretheonlyonewhoseadvicehemightlistento.I’dlikearoomwhosewindowlooksoutoverthesea.我想要一个窗朝大海的房间。3which指物。在句中作主语、宾语。Didyouseethemailwhichcameyesterday?NewYear’sEveisatimewhichIamlookingforwardto.Sheheardaterriblenoise,whichbroughtherheartintohermouth.4that既可指人，也可指物。作主语、宾语。Allthatisneededisasupplyofoil.ThepersonthattheywerelookingforwaslastseeninFuzhouRoad.留意：关系代词的省略(1)关系代词在定语从句中作宾语Ihavebeentothecity(which/that)youvisitedlastyear.Afterascoreofyears,Johnsonisnotthenaughtyboy(who/that)heusedtobe.(2)关系代词在定语从句中作表语二、关系副词的用法1where在定语从句中作地点状语，代指地点。常可由介词+which取代，如inwhich,onwhich,atwhich,etc.Potatocanbegrowninplaceswhereitistoocoldtogrowrice.(inwhich)2when在定语从句中作时间状语，代指时间。常可由介词+which取代，如onwhich,inwhich,duringwhich,etc.Ishallneverforgetthedayswhenweworkedonthefarm.(onwhich)3why在定语从句中作地点状语,可用forwhich替代。IhavecomearoundtoexplainthereasonswhyIwasabsentfromthemeeting.(forwhich)HaveatryHaveatry考点一：that和which3.先行词被theonly，thevery，thelast修饰时，用that。e.g.HeistheonlypersonthatIwanttoseenow.4.先行词同时指人和指物时，用that。e.g.Wetalkedaboutthethingsandpersonsthatwesawthen.5.定语从句内容为解释名词的性质、概念时，需用that。e.g.Aplaneisamachinethatcanfly.6.当主句是以who或which开头的特殊疑问句时。e.g.Whoisthepersonthatisstandingatthegate?（二〕以下情况，只能用which而不用that1引导非限制性定语从句Football,whichisaveryinterestinggame,isplayedallovertheworld.2在定语从句中做介词的宾语，且位于关系代词前时。I’mlookingforacontainerinwhichIcanputallthesepeaches.I’mlookingforacontainer_________Icanputallthesepeachesin.考点二：that和whowho，that在很多情况下可以通用，但是有些情况只能用who:1.先行词是one,ones,anyone的时候宜用who.Onewhohasnothingtofearforoneselfdarestotellthetruth.Theoneswhoflattermedon’tpleaseme.Don’ttellanyoneaboutthenewswhooughtn’