For example of a case:
(I was in home walking holding a jar of chocolate candy, I was gonna go to upstairs)
Mom: (She saw me and she called me from behind) "Where did you buy that?"
Me: (I was a bit startled, I turned back and showing up the jar) What?! This? <== I need chinese translation of the bold text.
How about "什么?!这个?” ?
吗after这个, i.e.这个吗? – Cocowalla Aug 13 '14 at 14:59