虚拟语气He talks as if he knew where she was .He talks as if he

虚拟语气
He talks as if he knew where she was .
He talks as if he had known where she was .这两句有什么差别,一个是与现在相反,一个是与过去相反,

第一句,与现在事实相反,意思是他说的好像他（现在）知道她在哪里.
第二句,与过去事实相反,意思是他说的好像他（过去的某个时间,那个时候）知道她在哪里.
再问： 第一句是不是其实他现在是不知道的，第二句是其实他过去是不知道的？
再答： 恩，对的，虚拟语气就是与事实相反。