the greatest natural sportsmen of modern times 
(ROOT (NP (NP (DT the) (JJS greatest) (JJ natural) (NNS sportsmen)) (PP (IN of) (NP (JJ modern) (NNS times)))))
(ROOT (NP (NP (DT ) (JJS ) (JJ ) (NNS )) (PP (IN ) (NP (JJ ) (NNS )))))