爱华网asto/as for
(1)as for
Øas for用来转换话题：用来引出另外一方或者新的谈话内容，但与前文内容也有一定的联系，起到补充前文又突出后文的作用，使之与前文形成对照。
例：你可以睡在床上，至于这些孩子，他们只能睡地板了。You can have a bed, but as for thechildren, they have to sleep on the floor.
例：在乡下我们度过了一个愉快的周末。至于交通，我们没有遇到任何困难。We had a delightful weekend in thecountry. As for the traffic, wehad no difficulty.
Øas for还经常用来表示亲蔑、冷淡的态度的。
例：至于John，我再也不想见到他了。As for John, I never want to want tosee again.
例：我只想叫你来，至于其他人，我不在乎。I only want you to come; as for others, Idon’t care.
例：至于回去，那是不可能的。As for going back, that is out of thequestion.
(2)as to
Øas to在表示“关于”“至于”时，一般情况下意义和功能类似于with regard to, regarding,concerning等。
Øas to可用于引出一个与前文有所不同的话题，此时与as for表示话题转换的意义相似，但比as for更为正式，但一般情况下，as for 更强调话题的转换。
例：…至于那个技术问题，我以后再详细讲。…As to that technical problem, I willdeal with it in detail later.
Øas to用以重提旧事：as to引出的内容是前文曾经提到过的或者谈话对方都有所了解的，表示“说到”之义。
例：至于你提出的事项，我认为应当尽快解决。As to the matter you brought up, I thinkit should be settled as speedily as possible．
例：至于你上次信中提及的问题，我无法回答。As to the question you raised in your lastletter, I think that it is unanswerable．
Øas to常与表示询问、争论、疑问等动词连用。
例：我对你女儿的能力一点也不怀疑。I have no doubts as to your daughter’sability.
Øas for后面通常直接名词或动名词，as to后面可接动名词、名词从句或疑问词+不定式的短语
例：He asked my advice as to what to do.[接疑问词+不定式]
例：We made enquiries as to when the nexttrain would be leaving. [接名词从句]
例：I am terribly uncertain as to whether heis the right man for me. [接名词从句]
（由得法翻译总结和整理）
