宾语从句置于及物动词后,做宾语.表语从句置于联系动词后,做表语.表语是用来说明主语的身份、特征和状态的,它的位置在连系动词（to be,to become,to appear,to look,to seem 等）之后,可以作表语的有：名词、代词、形...