定语从句一﹑概念定语从句是指在句子中起定语作用、修饰句中名词或代词的从句，其中被修饰的名词或代词称为先行词。定语从句一般紧跟在它修饰的先行词之后，在先行词和定语从句之间起连接作用的词叫做关系词。关系词有关系代词和关系副词两种。定语从句就其与先行词的关系，可以分为限制性定语从句和非限制性定语从句。限制性定语从句与先行词的关系十分密切，如果去掉该从句，主句意思就不能表达完整。通常情况下，朗读时中间没有停顿，从句和主句之间不用逗号分开。非限制性定语从句与先行词的关系很松散，去掉从句，主句意思仍然清楚，从句只是作附加说明。朗读时中间一般有停顿，从句和主句之间用逗号分开。例：YesterdayImetoneofmyfriends,whoseemedtobeverybusy.Theywanttosetupacountryoftheirown,wheretheycanbetheirownmasters.Isawsomethinginthepaperwhichmightinterestyou.语法上，非限制性定语从句一般不用that.二、关系代词引导的定语从句：1、当先行词是物的时候：引导词可能是that、which、whose。that、which：用于先行词在从句中充当主、宾。whose：表示先行词和引导词后面的名词构成从属关系.Isawsomethinginthepaperwhichmightinterestyou.2、当先行词是人的时候：引导词可能是that、who、whom、whose。whose：表示先行词和引导词后面的名词构成从属关系，做定语。当先行词在从句中充当宾语，引导词可以用who、whom、that。当先行词在从句中充当主语，引导词只能用who。三、关系副词的用法关系副词主要有when,where,why等，在定语从句中作状语，分别表示时间、地点和原因。Wednesdayisthedaywhentheshopsarenotopenintheafternoon.Givemeonereasonwhyweshouldhelpyou.要特别注意：activity,case,point,even,situation,job,organization,position等抽象名词后接where引导定语从句的用法Idon’twantajobwhereI’mchainedtoadeskallday.Today,we’lldiscussanumberofcaseswherebeginnersofEnglishfailtousethelanguageproperly.四、在定语从句中，which和that在指代事物时，一般可以互换使用，但并非在任何情况下都是这样，宜用that,而不宜用which的情况有：①先行词为不定代词时,all,much,something,everything,anything,nothing,none,theone等,Weshoulddoallthatisusefultothepeople.There'snothingthatcanbesaidaboutit.Doyoumeantheonethatwasboughtyesterday?②先行词被only,any,few,little,no,just,very,oneof等词修饰时。Theonlythingthatwecoulddowastowait.That'stheverywordthatiswronglyused.IhopethelittlethatIcanwillbeofsomehelptothem.比较*Thisisoneofthebestnovelsthatwerepublishedlastyear.*Thisistheonlyoneofthebestnovelsthatwaspublishedlastyear.（“Oneofthe+复数名词”后面定语从句中谓语用复数，如果oneof+复数名词这一结构前面带有theonly、thevery之类的限定语，后面定语从句的谓语动词则要用单数形式。）③先行词是序数词时或被序数词修饰时。1.WhenwetalkaboutWuxi,thefirstthatcomesintomindisTaiLake.2.Thisisthethirdfilmthathasbeenshowninourschoolthisterm.④先行词是最高级或被最高级修饰时。1.Thisisthebestthatcanbedonenow.2.Themostimportantthingthatshouldbedonerightnowishowtostophimfromgoingon.⑤先行词既有人又有物，用which和who都不适合，这时宜用that.如：1.Thewriterandhisnovelthatyouhavejusttalkedaboutisreallywellknown.2.Theriderandhisbikethathadrunoveranoldwomanwereheldupbythepolice.⑥被修饰词为数词时.1.YesterdayIcaughttwofishandputtheminabasinofwater.Nowyoucanseethetwothatarestillalive.⑦如果有两个从句，其中一个关系代词已用which,另一个关系代词宜用that。Edisonbuiltupafactorywhichproducedthingsthathadneverbeenseenbefore.⑧疑问词是who或which，关系代词宜用that，以避免重复。1.Whichisthebookthatyoulikebest?2.Whoisthemanthatisstandingatthegate?⑨主句是Therebe结构，修饰其主句的定语从句宜用that作关系代词.如：Thereisstillaseatinthecornerthatisstillfree.五...
