that sometimes it 's difficult to tell who the other actors in the movie are 
(ROOT (SBAR (IN that) (S (ADVP (RB sometimes)) (NP (NP (PRP it))) (VP (VBZ 's) (ADJP (JJ difficult)) (S (VP (TO to) (VP (VB tell) (SBAR (WHNP (WP who)) (S (NP (NP (DT the) (JJ other) (NNS actors)) (PP (IN in) (NP (DT the) (NN movie)))) (VP (VBP are)))))))))))
(ROOT (SBAR (IN ) (S (ADVP (RB )) (NP (NP (PRP ))) (VP (VBZ ) (ADJP (JJ )) (S (VP (TO ) (VP (VB ) (SBAR (WHNP (WP )) (S (NP (NP (DT ) (JJ ) (NNS )) (PP (IN ) (NP (DT ) (NN )))) (VP (VBP )))))))))))