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A. I've never known about the rules until now after your explanation.

B. I never knew about the rules until now after your explanation.

C. I didn't ever know about the rules until now after your explanation.

1. Which of the above sentences are grammatically correct?
2. If two or all are correct, what's the difference in meaning?
3. Which are natural?

In my opinion, A is correct because of the phrase "until now", though I'm not quite sure. Please advice. Thanks.
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In order of naturalness, with most natural first and least natural last, I'd go:

"I didn't know about the rules until now."

"I never knew about the rules until now."

"I've never known about the rules until now."

"I didn't ever know about the rules until now."
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Thanks so much for your answers.

Do you think this one is okay?

I didn't know about the rules until now -- after what you had explained.

My friend and I were discussing and he said "...after your explanation" in my original sentence sounds odd. I guess it's also the reason why you omitted it in your answers. Would you agree? Thanks.
AnonymousDo you think this one is okay?

I didn't know about the rules until now -- after what you had explained.

My friend and I were discussing and he said "...after your explanation" in my original sentence sounds odd. I guess it's also the reason why you omitted it in your answers. Would you agree? Thanks.
Yes, I omitted it because it didn't look quite right, and I didn't want to complicate my answer by going into details about something that didn't seem relevant to your question. I don't think your alternative above is any better (actually, I think it's worse).

In conversation one might say: "I didn't know about the rules until now ... after your explanation", where "after your explanation" is an afterthought. When committing this to writing (unless transcribing actual dialogue, of course) it seems loose. A better better way of putting it might be: "I didn't know about the rules until you explained them just now".
So my original sentence is fine in convesation, but not in writing. Thank you for improving my sentence. I really appreciate it.
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