【上期回顾】

【本期内容】

一、内容纲要

二、内容简述

（一）定义

用来充当另一个句子的定语的句子，叫作定语从句。

根据定语从句与其所修饰的成分之间的关系，可以分为限定性定语从句和非限定性定语从句。

（二）两个概念

1、先行词

定语从句所修饰的名词或代词，叫作先行词，一般都位于定语从句前面。如：

The man who is standing under the tree is his father.

上句中的the man被定语从句who is standing under the tree所修饰，就是先行词。

2、关系代词或关系副词

用来连接定语从句的代词或副词，叫作关系代词或关系副词。

常见的关系代词主要包括：who, whom, whose, which, that。

常见的关系副词主要包括：why, when, where。

（三）限定性定语从句

当定语从句对先行词起着修饰限定的作用时，叫作限定性定语从句。如：

We are looking for a girl who has long hair and blue eyes.

This is the city which she visited last year.

I can still remember the day when they got married.

（四）非限定性定语从句

当定语从句对先行词起着补充说明的作用时，叫作非限定性定语从句，一般会通过逗号，将从句与先行词分开。如：

His mother, who is a doctor, is expert at calligraphy.

The Great Wall, which enjoys a very long history, is the symbol of China.

【注意】

一般来说，当先行词具有唯一性时，其后的定语从句一般都是非限定性定语从句。

（五）关系代词或关系副词

关系代词或副词的选择主要取决于现行词是表人还是表物，以及先行词在从句中充当什么成分，即从句缺什么成分。

作主语

作宾语

作定语

作状语

表人

who, that

who, whom, that

whose

why, when, where

表物

which, that

which, that

whose

（六）特殊情况

1、关系代词只能用that的情况

当先行词含有序数词、最高级、不定代词等时，一般用关系代词that来连接定语从句。如：

This is the best film that I have ever seen.

He is the third student that has won the competition.

2、关系代词不能用that的情况

当先行词后紧跟着介词，其后不能用that，who也不能跟在介词后面。此外，that和why也不能用来连接非限定性定语从句。如：

Jack is the student to whom I was talking just now.

The tree from which the village had made a lot of money was cut down last week.

That is the reason why she was late for school this morning.