主语从句和同位语从句的区别不是，主语从句去掉从句就缺主语了，而同位语中去掉后，不缺成分，谁能举几个例子说明一下啊

～主语和谓语动词是句子必不可少的主要成分，缺一不可。
～用句子作主语就是主语从句，从句作主语是简单主语的扩展。
～主语从句和同位语从句都属于名词性从句，所不同的是主语从句是句子的主要成分，同位语从句则是附加成分。
～同位语从句是对抽象概念 (名词) 进行具体说明的附加成分，缺少以后不会破坏句子的完整性，却影响意思的明确性。例如：
The fact (that you were not in) made us disapointed that day. 事实让我们那天都很扫兴。
His suggestion (that we should make a decision as soon as possible) has been adopted. 他提出的建议已经被采纳。

主语从句:What I say is important.
That we got high marks makes us happy.
The message that he is a monster is a fact.
同位语从句:I will tell you a fact that he is a monster.