文档介绍：•几个基本概念
定语从句的定义：用作定语的从句叫定语从句。
先行词：被定语从句所修饰的名词或代词。
定语从句的位置：紧跟先行词（名词或代词）之后。
引导词：引导定语从句的词（包括关系代词和关系副词） 。
（1）关系代词：that/who/whom/which/as
（2 ）关系副词： when/where/why
引导词的位置：位于定语从句之前（先行词之后） 。【as除外】
引导词的功能（作用）：
（1） 连接先行词和定语从句。
（2） 在定语从句中充当一定的成分（关系代词充当主语或宾语，关系副词充当状语）
定语从句的类型：
（1）限定性定语从句（主句和定语从句之间无逗号 ）。
直接由引导词引导定语从句
The man who you' re talking to is my friend.
由介词+关系代词（whom/which ）弓|导
The man to whom you ' re talking is my friend.
I need a pen with which I can write a letter.
=1 need a piece of paper on which I can write a letter.
介词的选用可根据从句中的相关词组确定 ，该介词通常可以放在关系代词之前，也可放在从句之尾。
如：
The man (who/whom/that) I talked about at the meeting is from Beijing University.
=The man about whom I talked at the meeting is from Beijing University.
The palace (which/that) I often pay a visit to was built in the 17th century.
=The palace to which I often pay a visit was built in the 17th century.
(2)非限定性定语从句(主句和定语从句之间用逗号隔开 )。
直接由引导词引导定语从句。
由介词+关系代词(whom/which)引导。
I live in a house far away from the city, in front of which is a big tree.
There is an apple tree standing at the gate, on which are many apples.
This is the man to whom I gave the book.
either
由“代词/名词+of+whom/which ”或“ of which/ whom + 名词/代词”(先行词指 人用 whom,指物用 which)弓丨导。One, some, any, none, all, both, several, many, most, neither, 等词、数词、分数或百分比与 of whom或of which 连用。
He has five children, two of whom are abroad.
（比较