如:It remains to be seen whether he'll come here or not tomorrow. It remain to be seen whether... 这是一个比较常见的固定句型。 还有很多例句,只要句意通顺即可。 再如:It confuses me a lot how old he is. It hasn't been decided when the meeting will be held.
可以的。举个例子给你吧: That he has ever been here is known to all. 这里的That he has ever been here 是主语从句。 你如果用形式主语it将这个主语从句替换掉的话就成了It is known to all. 这个在语法上来说是没有问题的。 很高兴帮到你,还有疑问请追问!~