Never know where they won't turn up next. 
( Never ( ( know ( where ( they ( ( wo n't ) ( turn ( up next ) ) ) ) ) ) . ) )
(ROOT (S (NP (NNP Never)) (VP (VBP know) (SBAR (WHADVP (WRB where)) (S (NP (PRP they)) (VP (MD wo) (RB n't) (VP (VB turn) (ADVP (RB up) (JJ next))))))) (. .)))
It's hard to predict where they will turn up.
( It ( ( 's ( hard ( to ( predict ( where ( they ( will ( turn up ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (PRP It)) (VP (VBZ 's) (ADJP (JJ hard) (S (VP (TO to) (VP (VB predict) (SBAR (WHADVP (WRB where)) (S (NP (PRP they)) (VP (MD will) (VP (VB turn) (PRT (RP up))))))))))) (. .)))