['he', 'choose', 'operate', 'EmptyParameter', 'EmptyParameter'] ['he', 'operate', 'EmptyParameter', 'Harry', 'on']
['<PRP>', 'get-13.5.1', 'other_cos-45.4', 'EmptyParameter', 'EmptyParameter'] ['<PRP>', 'other_cos-45.4', 'EmptyParameter', 'harry', 'on']
He chose to operate on Harry because he was his friend.
<PRP> chose to operate on harry because <PRP> was <PRP> Synset('person.n.01').