understand the difference between dumb fun and just plain dumb 
(ROOT (S (VP (VB understand) (NP (NP (DT the) (NN difference)) (PP (IN between) (NP (NP (JJ dumb) (NN fun)) (CC and) (ADJP (RB just) (RB plain) (JJ dumb))))))))
(ROOT (S (VP (VB ) (NP (NP (DT ) (NN )) (PP (IN ) (NP (NP (JJ ) (NN )) (CC ) (ADJP (RB ) (RB ) (JJ ))))))))