Where is, where was this?
( ( Where is ) ( , ( where ( ( was this ) ? ) ) ) )
(ROOT (SBARQ (SBAR (WHADVP (WRB Where)) (S (VP (VBZ is)))) (, ,) (WHADVP (WRB where)) (SQ (VBD was) (NP (DT this))) (. ?)))
I know where it happened.
( I ( ( know ( where ( it happened ) ) ) . ) )
(ROOT (S (NP (PRP I)) (VP (VBP know) (SBAR (WHADVP (WRB where)) (S (NP (PRP it)) (VP (VBD happened))))) (. .)))