to his supple understanding of the role 
(ROOT (PP (IN to) (NP (NP (PRP$ his) (JJ supple) (NN understanding)) (PP (IN of) (NP (DT the) (NN role))))))
(ROOT (PP (IN ) (NP (NP (PRP$ ) (JJ ) (NN )) (PP (IN ) (NP (DT ) (NN ))))))