History of pulmonary embolism.
 patient has no history of PE
(ROOT (NP (NP (NP (NN History)) (PP (IN of) (NP (JJ pulmonary) (NN embolism)))) (. .)))
(ROOT (S (NP (NN patient)) (VP (VBZ has) (NP (NP (DT no) (NN history)) (PP (IN of) (NP (NN PE)))))))
( ( History ( of ( pulmonary embolism ) ) ) . )
( patient ( has ( ( no history ) ( of PE ) ) ) )