Negative questions

This is how negative questions are formed:-

√ Are you from Vietnam? →X Aren’t you from Vietnam?
√ Do you work in an office? →X Don’t you work in an office?
√ Did she go to the party? →X Didn’t she go to the party?
√ Is that your mobile phone? →X Isn’t that your mobile phone?
√ Have you seen my bag? →X Haven’t you seen my bag?
√ Will you help us? →X Won’t you help us?
√ Would you like some water? →X Wouldn’t you like some water?
√ Was the food good? →X Wasn’t the food good?
√ Can he come on time? →X Can’t he come on time?
√ They like cats. →X Don’t they like cats?
√ That was a great film. →X Wasn’t that a great film?
√ He has been to Vietnam. →X Hasn’t he been to Vietnam?
√ I paid by credit card. →X Didn’t I pay by credit card?

Negative questions are used to show:-
surprise e.g. Aren’t you supposed to be at work now?
anger e.g. Why didn’t you call me?
Uncertainty e.g. Isn’t her name Pam?