英语从句按成分为，主语从句，定语从句，表语从句，宾语从句，状语从句，同位语从句六类，例句主语从句the boy who he is wearing the red is my cousin.(穿红衣服的男孩是我表弟)，定语从句the girl who she stood here just now is our school(刚才站这儿的女孩是我们学校的)，表语从句this is only a chair that it is a red here(这是这儿的唯一一把红色的椅子)。