As to 與As for 的分別

兩者也解至於, 例如: My father has retired. As for my mother, she will retire soon.

留意兩者都不能用在文章的開頭, 因為As to 和As for 都是轉折詞, 是繼承前面的說話.

而兩者分別在於, As to 可跟wh-clause, 例如:

I have no idea as to where he has gone. 

I am uncertain when he will be back.