predominantly amateur cast is painful to watch , so stilted and unconvincing 
(ROOT (S (NP (ADJP (RB predominantly) (JJ amateur)) (NN cast)) (VP (VBZ is) (ADJP (ADJP (JJ painful) (SBAR (S (VP (TO to) (VP (VB watch)))))) (, ,) (ADJP (RB so) (JJ stilted) (CC and) (JJ unconvincing))))))
(ROOT (S (NP (ADJP (RB ) (JJ )) (NN )) (VP (VBZ ) (ADJP (ADJP (JJ ) (SBAR (S (VP (TO ) (VP (VB )))))) (, ) (ADJP (RB ) (JJ ) (CC ) (JJ ))))))