其实结构相似但不相同,形似而神散,
It is + 形容词、动词的现在分词/过去分词 + 主语从句
It is important that teachers respect their students.
It is believed that dogs know men by smell.
It is interesting that nobody knew it.
It is (was)+ 名词、代词、介词短语 + that + 句子
I saw a man naked running in Quancheng Square last night.
It was I that saw a man naked running in Quancheng Square last night.
It was a man naked that I saw running in Quancheng Square last night.
It was in Quancheng Square that saw a man naked running last night.
It was last night that I saw running in Quancheng Square.