核心问题
“Has Smith been ill?” ____ “Not that I know of.” (= I'm not aware of his having been ill.) (史密斯病了吗？——我一点也不晓得。)(钱歌川编著《英文疑难详解续篇》，p.281)
上句中的 Not that I know of 我认为并不是指“我一点也不晓得”，而是指“据我所知，他没有病”。不知我的译法对否？
词典解答
你的译法是正确的。上面的 that 从句叫做限制性状语从句。这里的 that 相当于 as far as(就……而言)，但是只能位于句末，而且主句总是否定的。让我们考察一下英英词典的解释：
- “Note also the phrase not that I know of, used as a qualified negative, meaning ‘not as far as I know.’”
I saw the doctor come out of the house next door to you this morning. Is there someone ill there?
—Not that I know of." (F. T. Wood: English Prepositional Idioms, p. 327)
- You say "Not that I know of" when someone asked you whether or not something is true and you think is "no", but you cannot be sure because you do not know all the facts. (EED) 再看下列实例：
A: Was nobody else there? B: Not that I know of.
甲:那里没有别人吗?乙:据我所知没有。(《英汉大词典》,p.1804)