I think __silly __you not to forgive others for their mistakes.

问题描述:

I think __silly __you not to forgive others for their mistakes.
A it for B it's of C that's of D it's for
但是第一个空为什么不是it?

这是一个宾语从句,I think 是主句,剩下的做think的从句,从句也是一个完整的句如果用it就少了动词,所以要用it's,有了is就是一个完整句子了