cast is painful to watch 
(ROOT (S (NP (VBN cast)) (VP (VBZ is) (ADJP (JJ painful) (SBAR (S (VP (TO to) (VP (VB watch)))))))))
(ROOT (S (NP (VBN )) (VP (VBZ ) (ADJP (JJ ) (SBAR (S (VP (TO ) (VP (VB )))))))))