may puzzle his most ardent fans . 
(ROOT (S (VP (MD may) (VP (VB puzzle) (NP (PRP$ his) (ADJP (RBS most) (JJ ardent)) (NNS fans)))) (. .)))
(ROOT (S (VP (MD ) (VP (VB ) (NP (PRP$ ) (ADJP (RBS ) (JJ )) (NNS )))) (. )))