《新英汉词典》等工具书均将 as for 和 as to 译为“至于”“关于”“说到”。不知它们之间是否有区别？
用于句首的 as for 与 as to 意义很相近, 它们都能引出一个与前一个话题稍微有些不同的话题。但 as for 在语体上不如 as to 正式，并且着重话题的转换，也就是说，它所引导的是前面尚未提到过的新的事情，因此，它不能用于文章的开头。
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We had a delightful weekend in the country. As for the traffic, we had no difficulty. (CGEL) 在乡下我们度过了一个愉快的周末。至于交通，我们没遇到任何困难。
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Much pasture land is under water; and as for the grain, most of that has been ruined. (CEU) 大部分牧场都进了水, 至于谷物, 则大部分都被冲毁了。
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As to the journey, we must decide about that later. (Palmer) 关于旅行, 我们必须以后再作决定。
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As to that, I haven't decided yet. (LDCE) 关于那件事,我尚未做出决定。
as to 常常与 wh-疑问词引导的动词不定式和名词从句连用(有时可省略), 而 as for 却没有此种用法:
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Nobody could decide(as to) what to do. (LDCE) 谁也不能决定该做什么。
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He's very uncertain as to whether it's the right job for him. (LDCE) 关于他究竟是否适合做这项工作，他实在拿不准。
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The numbers are a hint as to how to decipher the rest of the message. (Dan Brown, The Da Vinci Code) 这些数字是破译其他信息的线索。(《达·芬奇密码》)