含有主语从句的复合句是怎样的能举个例子再详细的分析下吗?

主语从句一般有两种形式,有逻辑主语(引导词)和无逻辑主语:
1、带逻辑主语的句型:It is …that.it就是逻辑主语,that引导的是主语从句.例子:It is intereting that a cat can make friend with a mouse.
2、无逻辑主语的句型:一般是用what.How.Which.Where等特殊疑问代词、连词引的完整句子+is+that….例子:What l said is that you must complete your job on time.How you deal with the man is very important.Which boy broke the window is not the key matter in this case.

that引导时，在从句中不做成分，也没有实际意义，但不可省略that the moon travels around the earth once every month is known to everyone.

主从复合句，既然是复合句。顾名思义就是两句话。含有主语从句的复合句就是句子做主语。
eg：it is important that study hard
这句话中 that studying hard是从句。从翻译的角度上讲：努力学习是重要的 学习是v-ing作S（主语）
努力学习就是主语从句