定语从句的分类：

　　限制性定语从句和非限制性的定语从句:

　　限制性定语从句不用逗号与主句分开,对所修饰的词起特指或限定的作用,去掉后意思不完整或不太清楚.翻译成中文时,一般把定语从句翻译在先行词之前.

　　引导限制性定语从句的关系代词有who, whom, whose, that, which, of which和关系副词when, where, why等.

　　eg. This is the man who helped me.

　　I was the only person in our office that was invite to the palace ball.

　　非限制性的定语从句和主句之间往往用逗号分开,只对被修饰的词语或主句起补充说明的作用,去掉后对句意影响不大.翻译时通常把定语从句翻译在先行词后边,作为附加说明.

　　引导非限制性定语从句的关系代词有who,whom, whose, which, as和关系副词when, where,一般不用that 引导.

　　eg. I have two sisters, who are both doctors.

　　Last Sunday they reached Shanghai, where a meeting was holding.

　　动词根据其后是否带有宾语,可分为两类,分别是：及物动词（Transitive Verb）、不及物动词（Intransitive Verb）,缩写形式分别为vt. 和vi..