一、定语从句的功用和结构

　　在复合句中，修饰某一名词或代词的从句叫做定语从句。被定从句修饰的词叫做先行词。定语从句必须放在先行词之后。引导定语从句的关联词有关系代词和关系副词。例如：

　　This is the present that he gave me for my birthday

　　二、关系代词和关系副词的功用

　　关系代词和关系副词用来引导定于从句，在先行词和定语从句之间起纽带作用，使二者联系起来。关系代词和关系副词又在定语从句中充当一个成分。关系待客做主语，宾语，定语，关系副词可作状语。

　　1. 作主语：关系代词在定语从句中作主语时，从句的谓语动词的人称和数须和先行词一致。例如：　

　　I don’t like people who talk much but do little.

　　The cars which are produced in Hubei Province sell very well.

　　2. 作宾语：She is the person that I met at the school gate yesterday.

　　The book that my grandmother gave me is called “The Great Escape”.

　　3. 作定语

　　关系代词whose在定语从句中作定语用。例如：

　　What’s the name of the young man whose sister is a doctor?

　　The girl whose father is a teacher studies very hard.

　　4. 作状语     

　　I’ll never forget the day when I first came to Beijing.

　　三、各个关系代词和关系副词的具体用法

　　1. who 指人，在定语从句中作主语。例如：

　　The person who broke the window must pay for it.

　　The boy who is wearing the black jacket is very clever.

　　2. whom指人，在定语从句中作宾语。例如：

　　Do you know the young man (whom) we met at the gate？

　　Mr Lee (whom) you want to see has come.

　　3. whose 指人，在定语从句中作定语。例如：

　　The girl whose mother is ill is staying at home today.

　　I know the boy whose father is a professor.

　　4. which指物，在定语从中作主语或宾语。例如：

　　A dictionary is a book which gives the meaning of words.

　　Here is the book (which) the teacher mentioned yesterday.