a 75-minute sample of puerile 
(ROOT (NP (NP (DT a) (NML (CD 75) (HYPH -) (NN minute)) (NN sample)) (PP (IN of) (NP (JJ puerile)))))
(ROOT (NP (NP (DT ) (NML (CD ) (HYPH ) (NN )) (NN )) (PP (IN ) (NP (JJ )))))