of a film that 's rarely as entertaining as it could have been 
(ROOT (PP (IN of) (NP (NP (DT a) (NN film)) (SBAR (WHNP (WDT that)) (S (VP (VBZ 's) (ADVP (RB rarely)) (ADJP (ADJP (RB as) (JJ entertaining)) (SBAR (IN as) (S (NP (PRP it)) (VP (MD could) (VP (VB have) (VP (VBN been)))))))))))))
(ROOT (PP (IN ) (NP (NP (DT ) (NN )) (SBAR (WHNP (WDT )) (S (VP (VBZ ) (ADVP (RB )) (ADJP (ADJP (RB ) (JJ )) (SBAR (IN ) (S (NP (PRP )) (VP (MD ) (VP (VB ) (VP (VBN )))))))))))))