is n't as compelling or as believable as it should be . 
(ROOT (S (VP (VBZ is) (RB n't) (ADJP (ADJP (ADJP (RB as) (JJ compelling)) (CC or) (ADJP (RB as) (JJ believable))) (SBAR (IN as) (S (NP (PRP it)) (VP (MD should) (VP (VB be))))))) (. .)))
(ROOT (S (VP (VBZ ) (RB ) (ADJP (ADJP (ADJP (RB ) (JJ )) (CC ) (ADJP (RB ) (JJ ))) (SBAR (IN ) (S (NP (PRP )) (VP (MD ) (VP (VB ))))))) (. )))