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