should have been the ultimate imax trip 
(ROOT (VP (MD should) (VP (VB have) (VP (VBN been) (NP (DT the) (JJ ultimate) (NN imax) (NN trip))))))
(ROOT (VP (MD ) (VP (VB ) (VP (VBN ) (NP (DT ) (JJ ) (NN ) (NN ))))))