题目内容：

i would have asked him to attend our gathering but i( didn`t know) his address.
i would write to her,but i don`t know her address.这两句话有什么区别,为什么上面的用didn`t后面的用don`t?

优质解答

这两句前半句都是虚拟语气,后半句都是具体事实,
第一句从would have done可知跟过去事实相反,后面的事实用过去式
第二句从would do判断跟现在事实相反,后面的事实就用现在时