['he', 'force', 'let', 'EmptyParameter', 'EmptyParameter'] ['he', 'let', 'they', 'EmptyParameter', 'EmptyParameter']
['<PRP>', 'urge-58.1', 'let-64.2', 'EmptyParameter', 'EmptyParameter'] ['<PRP>', 'let-64.2', '<PRP>', 'EmptyParameter', 'EmptyParameter']
He is forced to let them in.
<PRP> is forced to let <PRP> in.