does n't sustain interest beyond the first half-hour 
(ROOT (S (VP (VBZ does) (RB n't) (VP (VB sustain) (NP (NN interest)) (PP (IN beyond) (NP (DT the) (JJ first) (NN half) (HYPH -) (NN hour)))))))
(ROOT (S (VP (VBZ ) (RB ) (VP (VB ) (NP (NN )) (PP (IN ) (NP (DT ) (JJ ) (NN ) (HYPH ) (NN )))))))