are well worth revisiting as many times as possible 
(ROOT (VP (VBP are) (ADJP (RB well) (JJ worth) (S (VP (VBG revisiting) (NP (NP (ADVP (RB as) (JJ many)) (NNS times)) (PP (IN as) (ADJP (JJ possible)))))))))
(ROOT (VP (VBP ) (ADJP (RB ) (JJ ) (S (VP (VBG ) (NP (NP (ADVP (RB ) (JJ )) (NNS )) (PP (IN ) (ADJP (JJ )))))))))