marveling at these guys ' superhuman capacity 
(ROOT (S (VP (VBG marveling) (PP (IN at) (NP (NP (DT these) (NNS guys) (POS ')) (JJ superhuman) (NN capacity))))))
(ROOT (S (VP (VBG ) (PP (IN ) (NP (NP (DT ) (NNS ) (POS )) (JJ ) (NN ))))))