定语从句在高考英语中，是一个高频考点，在听力，单选，完型，阅读中均大概率出现，如果在写作中能正确使用一个漂亮的定语从句也会让考生得到阅卷老师的青睐，但是，定语从句又涉及很多复杂的用法，让很多同学感到很头疼。

本文归纳了高中英语定语从句的用法，不同关联词的适用情况，解题难点和关键，列举了种种特殊情况，对比了限制性定语从句和非限制性定语从句，记住这些，多加练习，高考英语提高5分不是问题。

一、定语从句解题关键概括

1．定语从句三步：第一找出先行词；第二看先行词在定语从句中的语法功能（做主语、宾语或状语）；第三选择合适的关联词。

2．定语从句在选择关连词that 与which时，常常容易出错，所以应记住什么时候只能用that，什么时候只能用which.

（1） 只能用 that 的情况归纳4种：即先得词被序数词最高级修饰过；先行词为all 、everything、nothing等不定代词；先行词同时是人和物并列时；最后先行词分别被the only 、the very the same、the last 修饰。请看下列四组例句，注意其先行词：

① The first thing that we should do is to work out a plan .

② I t almost seemed as if the good man were trying to teach us all that he knew at this lesson .

③ Later my father and Mr.Crosset talked for about half an four of things and persons that they remembered in school.

④This is the very dictionary that I want to find .

（2）只用which 情况有两种情况：一是非限制性定语从句，关连词要用which；二是做介词宾语时只能用which。请看下列两组例句：

① I said nothing, which made him more angry .

② I have the book about which you are talking .

二、在定语从句的非限制性定语中，which 和as 是容易混淆的。在很多情况下两者兼可互换，但在下列情况中不可互换：

1、通常As 可以放在整句的句首，而which，只能在逗号之后，as 本身含有“正如”，as 在定语从句中既可是主语也可做宾语

① As appear from her paper, she has read widely in Romantic literature.

② She is remarkable, as I have told you .

2、 which 在做非限制性定语从句关联词时可以无明确先行词，指前句整个的意思，如：she has warried again, which surprises us .

三、在定语从句中，许多人往往分不清all that 和what ,what 实际上只引导名词性从句，它相当于all that两个字，例如：

All that I know is that he has made up his mind to heave the country for a new place.

= what I know is that ……

四、限制性定语从句和非限制性定语从句解题关键详述

一、限定性定语从句：

注：先行词是time, minute, moment, next time很少用关系副词when,可用that 但通常省去。

（2）非限制性定语从句

（2）限制性定语从句与非限制性定语从句的区别