Could someone help me to solve the following problems?

How long haven't you seen your parents?

My teacher told me that this question has some errors. But grammatically there's nothing wrong with the question at all. Is there something wrong with the word order or something else that I fail to pick up?

Thanks for your kindly help!

You wrote:

How long haven't you seen your parents?

It really should be: How long has it been since you've seen your parents?

:) hope that helps,
EbonyKisses

Try: "How long has it been since you've seen your parents?"
Or: "How long has it been since you saw your parents?"
A person of few words would probably say: "How long since you've seen your parents?" In actual speech, it's a rare person who speaks with grammatical precision and if you are portraying a character in a story you, as the author, have a right to make your characters speak any way you wish. Be careful, though, to be consistent, since your readers will pick up on it if you get careless.
Hope this helps a bit.
Harvey

Hi,

That's a hard question, but I think the 1 of the reasons it's wrong is because haven't is have not, so the question sounds weird when you put it like this: How long have not you seen your parents? And that's the problem. Try something else like How has it been since you've seen your parents? Or When is the last time you have seen your parents. Hope this helps a little.
-Nicole