You did, didn't you?"
( You ( ( ( ( did , ) ( ( did n't ) you ) ) ? ) '' ) )
(ROOT (S (NP (PRP You)) (VP (VBD did) (, ,) (SQ (VBD did) (RB n't) (NP (PRP you)))) (. ?) ('' '')))
You didn't do it, did you?
( ( You ( ( did n't ) ( do it ) ) ) ( , ( ( did you ) ? ) ) )
(ROOT (SINV (S (NP (PRP You)) (VP (VBD did) (RB n't) (VP (VB do) (NP (PRP it))))) (, ,) (VP (VBD did)) (NP (PRP you)) (. ?)))