is plenty of fun for all 
(ROOT (VP (VBZ is) (NP (NP (NN plenty)) (PP (IN of) (NP (NN fun)))) (PP (IN for) (NP (DT all)))))
(ROOT (VP (VBZ ) (NP (NP (NN )) (PP (IN ) (NP (NN )))) (PP (IN ) (NP (DT )))))