定语从句,作用相当于名词,通常由 that (既用余物又可用于人),which(一般只用来指物),who/whom(只用于指人)
e.g.I deserve more than the grade that/which I have been given.
The girl who is giggling over there is a beauty if her head were sacked.
宾语从句,相当于名词做宾语,由that引导,也可由连接代词或连接副词,还有what
e.g.We suspended that it was a trick to get our money.
Only you can decide who is the best chioce.
Tell me what you are thinking ahout the plan.
状语从句,作用相当于副词,是最复杂的一类从句,在句中的位置比较灵活,具体的引导词要根据不同类型的状语从句来定.
具体有以下几类:
1.时间状语从句,可由when,after,before,till(untill),since (这些是比较常用的)等来引导,有时状语从句也可以不由引导词来引导,而直接跟在一些表时间,频率的副词后.
e.g.When she pressed the button the lift stopped.
I have had another baby since I saw last time.
The boy didn't go to sleep untill his Dad came back.
I found the letter long after he had gone away.
(要去睡觉了,后面的,我以后在来接着写.或者推荐一本语法书)