they could have been in a more ambitious movie 
(ROOT (S (NP (PRP they)) (VP (MD could) (VP (VB have) (VP (VBN been) (PP (IN in) (NP (DT a) (ADJP (RBR more) (JJ ambitious)) (NN movie))))))))
(ROOT (S (NP (PRP )) (VP (MD ) (VP (VB ) (VP (VBN ) (PP (IN ) (NP (DT ) (ADJP (RBR ) (JJ )) (NN ))))))))