句子成分(主谓宾定状补)通常都是单词,这样的句子叫简单句.
如果句子里用另外一个句子做句子成分,那就是一个复杂句,而做成分的句子就叫做从句.
i saw him.这里主谓宾都是单词,是简单句
i saw that he was singing.
主句是I 谓语是saw 宾语是"that he was singing."这个句子,而这个句子就叫宾语从句.
与这个相似的还有,主语从句,定语从句,表语从句,状语从句等.
从属是属于的意思.
从结构上说,英语连接词分两大类：并列连词（coordinating conjunctions）和从属连词（subordinating conjunctions）. 从属连词这种连词是用以引导名词性从句和状语从句的,从属连词连接两个或两个以上的分句.
从属连词连接两个或两个以上的分句,形成复杂句中的从属分句.例如：
(4) He said that he did not want to go .
(5) Many things have happened since I last saw him.
(6) You may come if you want to.