___ is impossible for him to pass the English exam,for he never reads English.为什么填 It

___ is impossible for him to pass the English exam,for he never reads English.为什么填 It
___ is impossible for him to pass the English exam,for he never reads English.为什么填 It

___ is impossible for him to pass the English exam,for he never reads English.为什么填 It
这里It是形式主语.
固定句型,要记忆的.
你先这样理解吧.
更深层次的理解是,这里It替代的是to pass the English exam,for he never reads English动词不定式短语.这是为了避免头重脚轻的形式.
所以你再看看如果除去It,那么这句话就应该这样写了,to pass the English exam,for he never reads English is impossible for him.你看看是不是头重脚轻,虎头蛇尾阿.这就是英语的形式美的其中一个体现.