you did you see that
( you ( did ( you ( see that ) ) ) )
(ROOT (S (NP (PRP you)) (VP (VBD did) (SBAR (S (NP (PRP you)) (VP (VBP see) (NP (DT that))))))))
I saw that!
( I ( ( saw that ) ! ) )
(ROOT (S (NP (PRP I)) (VP (VBD saw) (NP (DT that))) (. !)))