it 's hard to say who might enjoy this 
(ROOT (S (NP (NP (PRP it))) (VP (VBZ 's) (ADJP (JJ hard)) (S (VP (TO to) (VP (VB say) (SBAR (WHNP (WP who)) (S (VP (MD might) (VP (VB enjoy) (NP (DT this))))))))))))
(ROOT (S (NP (NP (PRP ))) (VP (VBZ ) (ADJP (JJ )) (S (VP (TO ) (VP (VB ) (SBAR (WHNP (WP )) (S (VP (MD ) (VP (VB ) (NP (DT ))))))))))))