a. 定语从句概述

i. 用句子来修饰名词，对名词进行限制
ii. 定于从句连个重要概念，先行词和关系词

1. 先行词：被定语从句修饰的对象
2. 关系词：指代先行词，连接作用

b. 关系词在定于从句中充当的成分

i. 关系词用作从句的主语
ii. 关系词用作从句的宾语
iii. 关系词用作从句中介词的宾语
iv. 关系词作宾语可以省去，不论是作动词还是介词

c. 关系词与先行词的搭配关系

i. 先行词指人用who 或whom

1. 指人才能用who或whom
2. Who和whom区别
   a. Who是主格形式，所以介词后面不能用who，而是whom.
   b. Whom在定于从句中不能作主语，可做宾语和表语

ii. 表示人和物的所有关系，用whose ，其作用类似于物主代词my,your,her,his,their,our,whose

iii. 先行词指“物”，用关系代词 which。造句结构类似于who，可做从句主语或宾语，不过which的先行词时物

1. 先行词是单个名词 Anger is a wind which blows out the lamp of the mind
2. 先行词是一个短语 He likes climbing mountains, which is a good exercise.
3. 先行词时一个句子 Tom was late，which surprised me.

iv. That 可以指代人，也可以指代物

1. 先行词同时出现人和物时，用that The writer and his novels that the article deals with are quite familiar to us.
2. 先行词指“物”的all,little,few,much,none,the first时，用that . All that glitters is not gold.
3. 先行词是不定代词something, anything, nothing,everything时，一般用that
4. 先行词被any,only,every,no some,much,few,little,序数词，形容词的最高级，the only,the one,the very,the right,the last等成分修饰时，用that He is the only man that can speak four foreign languages in our company.
5. That不用在非限制性定语从句中 I became a single mother overnight, which is nothing like becoming famous overnight.
6. That 不能用于介词后面 the world in which we live is made up of matter/the world that we live in is made up of matter

d. 关系副词的用法

i. When的用法

1. 先行词指时间 we will putting the outing until next week, when we won’t be so busy.
2. 关系副词when 在从句中作时间状语从句 注：若定于从句不是缺少状语，而是缺少主语或宾语，那么即使先行词时表示时间的名词，也不能用when，而用that 或which 来引导定语从句
   a. I’ll never forget the time which I spent on campus
   b. The day, which began brightly, ended with a violent storm

e. Where的用法

i. Where 先行词指地点
ii. 关系副词where在从句中作地点状语 ，若从句缺主语或宾语，则要用which 或that引导定于从句

1. This is the town which I told you before.
2. The library, which was built in 1930’s, needs to be renovated.

f. Why的用法，表示原因，只引导限制性定语从句