If I am asked the question: "John, have you ever talked to professor Jones about our son's behavior in class?"
Should I answer "Yes, I have." or "Yes, I did."

Also, can anyone help me with the negation? For example, should I say "he didn't return..." or "he hasn't returned..." what rule governs

Thanks a thousand times

1. "Yes, I have", "have" being the auxiliary used in the question.

2. I don't really understand your question. Your first example refers to a specific moment in the past, and your second one means that "he" isn't back yet... ?
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Thanks for replying,

I want to know if I should use "I didn't recognize you" or "I haven't recognized you"...What is the difference betwern the two of them?

It would depend on the context. Most probably, it would be "I didn't recognize you", because if you say the other one, you'd imply you still haven't recognized the person. Could you give us the context, please?