a hundred of them can be numbing 
(ROOT (S (NP (NP (DT a) (CD hundred)) (PP (IN of) (NP (PRP them)))) (VP (MD can) (VP (VB be) (ADJP (JJ numbing))))))
(ROOT (S (NP (NP (DT ) (CD )) (PP (IN ) (NP (PRP )))) (VP (MD ) (VP (VB ) (ADJP (JJ ))))))