：（1）同位（谓）语从句
s+vt + n +that+完整句
定语从句
s+vt+n+that(which)+不完整句
（2）在句中用作状语的从句叫状语从句
如：Where I live there are plenty of trees .
（地点）
He won”t be back until it is 10 o”clock
（条件）
（3）用作宾语的从句叫宾语从句，一般由that when……引导
如：I told him that it will be a good result .
（4）用作主语的从句叫主语从句，一般由what ,when , where ……引导
如：What I told him is right .