She was not able to speak, but appeared to comprehend well.
 Patient had aphasia
(ROOT (S (S (NP (PRP She)) (VP (VBD was) (RB not) (ADJP (JJ able) (S (VP (TO to) (VP (VB speak))))))) (, ,) (CC but) (S (VP (VBD appeared) (S (VP (TO to) (VP (VB comprehend) (ADVP (RB well))))))) (. .)))
(ROOT (S (NP (NN Patient)) (VP (VBD had) (NP (NN aphasia)))))
( ( ( ( ( She ( ( was not ) ( able ( to speak ) ) ) ) , ) but ) ( appeared ( to ( comprehend well ) ) ) ) . )
( Patient ( had aphasia ) )