an intelligent , realistic portrayal of testing boundaries 
(ROOT (NP (NP (DT an) (JJ intelligent) (, ,) (JJ realistic) (NN portrayal)) (PP (IN of) (NP (NN testing) (NNS boundaries)))))
(ROOT (NP (NP (DT ) (JJ ) (, ) (JJ ) (NN )) (PP (IN ) (NP (NN ) (NNS )))))