Dr. Nozkidz is in right now, and has opened the mailbag, to find a question from a reader! EE wants to know why the two following sentences are different. So… here goes…
” did you want to buy this new car, didn’t you?”
” didn’t you want to buy this new car, did you?”
Actually, these sentences are both incorrect.
They should be:
You did want to buy this new car, didn’t you?
You didn’t want to buy this new car, did you?
They are both tag questions.
Rather than tell you the answer, you can first read about it at http://a4esl.org/q/h/fb006-bp.html
The tag question in English is a phrase added to the main part of the sentence, inviting the listener to confirm or give an opinion about the comment. It is composed of two parts: the auxiliar verb, determined by the principal verb, in negative form (or affirmative if the principal verb is negative), followed by the pronoun, determined by the subject.
In your case, though, I think the speaker is trying to confirm the other person’s intentions by getting them to explain their point of view.
So, I could say: You do understand this explanation, don’t you? Meaning: I assume that you understand but I would like you tell me or confirm this to me.
For more information on Tag Questions, go to the BBC’s Learning English pages, especially the part on “When to use the tag questions” in the middle of the page. Scroll to find out.
Then you can try another practise if you wish at The English Zone.
Hope that helps.
Until next time… Noz.