['he', 'know', 'she', 'EmptyParameter', 'EmptyParameter'] ['he', 'come', 'EmptyParameter', 'EmptyParameter', 'EmptyParameter']
['<PRP>', 'comprehend-87.2', '<PRP>', 'EmptyParameter', 'EmptyParameter'] ['<PRP>', 'appear-48.1.1', 'EmptyParameter', 'EmptyParameter', 'EmptyParameter']
If he didn't know her, he wouldn't have come.
if <PRP> didn't know her, <PRP> wouldn't have come.