Quote:



But that is more a matter of semantics than grammar. We are more likely to want to contrast past and present states/habits in a negative question than in a positive one.



Or we are more likely to expect a positive answer to a negatively phrased question and a negative answer to a positively phrased one:

Didn't you use to have a motorbike?

Yeah, back in the '70s, when I was young and crazy.


Did you use to have a motorbike?

Nope, never. You wouldn't catch me on one of them death traps