"The shoe is on the other foot now, IS IT?"

I’m curious, why do you think Mary chose “is it” as a tag question, instead of “isn’t it”?
When do you use “is it” as a tag question in a declarative (opposite of “negative sentence”) sentence?


Interesting question. The usual form as you indicate, is negative statement followed by positive tag and vice versa. That’s used when you are seeking reassurance for what you say in your statement. But when you have positive statement followed by positive tag, what you are being is slightly sarcastic or you are expressing surprise as in: The shoe is on the other foot, is it - Oh now ! understand, now I see!


Thanks a lot for your detailed answer! I understand it now!