英语中的几种从句(句型),

有三大类
1.名词性从句 2.定语从句 3.状语从句
名词性从句中分：
1.主语从句：例,it is important to read book.(形主it作主语,真正的主语是to read book)
that air has pressure was known long ago.(关联词that引导的句子that air has pressure作主语从句)
2.宾语从句：I think it necessary that he should do his homework.(形式宾语it引导的)
I'm sure that my test will succeed.(sure后用that引导的宾从)
3.表语从句：系动词后的从句
it may be as you say(be是系动词,后面用as引导的)
this is that he is too young to go to school.(有系动词is,后面由that引导的表语从句)
4.同位语从句：同位语从句是对前面名词的解释说明,如：
The facts that he had done his homework.(事实就是he had done his homework,是对前面the facts的解释,是什么事实)
定语从句：在句子中起定语作用,修饰剧中的名词或代词的从句叫定从
例：the man (who is shaking hands with my father) is my teacher.(括号中就是定从,修饰限定the man)
BeiJin is a city (which has a long history).(括号中是定从,修饰the city)
状语从句：在复合句中担任状语成分的从句叫状语从句
例：I will tell her about that (when i see her).为时间状从
just stay (where you are).为地点状语
Because he is ill,he is absent today.为原因状语
这也很局限,其实要讲的还很多,你可以多看看语法书之类的