It is a pity that he could not come .这句话是主语从句吗?请分析一下句子成分,

It is a pity that he could not come .这句话是主语从句吗?请分析一下句子成分,
It is unusual for him to be late .这里的it是形式主语，to be late是真正的主语，麻烦分析一下句子成分，

He could not come 这件事情是一个遗憾.
It 是形式主语,真正的主语是that 引导的从句.
这句话就等于：That he could not come is a pity.
It is + 形容词 （for sb.) to do sth.to do sth 是真正的主语,it 只是形式主语.
你说得很对!很棒!
祝学习愉快!