today when i was paying, the cashier asked me , so you needn't any bag?
i answered ,yes, i needn't , i bring one.
actually, i doubted that i made a mistake.
because i am always confused with the usage like yes,(mean no), no(mean yes).
like yes, i do(negative meaning)
no, i don't(definitive meaning)
who can give me any examples to expain me? thanks!