一、定语从句的定义与分类
在复合句中，修饰某一名词或代词的从句叫定语从句，被修饰的名词或代词叫先行词。引导定语从句的有关系代词、关系副词和介词＋关系代词。定语从句一般放在先行词的后面。
根据定语从句与先行词的关系，定语从句可分为限制性定语从句及非限制性定语从句。
二、关系代词引导的定语从句
[观察典例]
They ignored the details which/that might account for the accident.
This is the suitcase (that/which)she is looking for.
The number of the people who/that come to visit this city each year reaches one million.
Danny was the man (who/whom/that) we rescued from the ruins.
I know the person whose house was totally destroyed in the earthquake.
It's the house whose door is painted red.
She is no longer the girl(that)she was ten years ago.
I hate the way (that)she always criticizes me.
