I didn't know I was wrong until now. (= But I know I was wrong now.)
I don't know/haven't found out if I'm wrong until now. (I still don't know)
The first 'until now' doesn't equal the second?
Thank you in advance.
It would be better to use 'yet' or 'so far'. In older texts, and in some mannered speech, you may also meet 'thus far'. The word 'heretofore' is similarly obscure (don't be intimidated by all those letters - it's pronounced as three words: 'here' + 'to' + 'fore'. 'Hitherto' (and its close relative 'thitherto', which instead of 'until now' it means 'until then') are too archaic to worry about.
Last edited by BobK; 20-Jan-2011 at 10:48. Reason: Added last sentence
I didn't realize until now that I was wrong.
I don't think your second sentence works. If you still don't know you are wrong, you can't say, "I still don't realize that I am/was wrong", or "I don't know that I am wrong yet" or however you want to phrase it.
Of course, the context might make it usable.
"I've heard nothing yet to show that I'm wrong."
"I'm still not convinced that I am wrong."
As the others have said, "until now" does tend to suggest that you 'now' realize you were wrong.
Then can we say 'Up to now/Up until now he's still here'?
Thank you again.