be careful what you wish for 
(ROOT (S (VP (VB be) (ADJP (JJ careful)) (SBAR (WHNP (WP what)) (S (NP (PRP you)) (VP (VBP wish) (PP (IN for))))))))
(ROOT (S (VP (VB ) (ADJP (JJ )) (SBAR (WHNP (WP )) (S (NP (PRP )) (VP (VBP ) (PP (IN ))))))))