['he', 'explain', 'event', 'EmptyParameter', 'EmptyParameter']
['<PRP>', 'indicate-78', "Synset('natural_phenomenon.n.01')", 'EmptyParameter', 'EmptyParameter']
He can explain the events to his superiors.
<PRP> can explain the Synset('natural_phenomenon.n.01') to <PRP> Synset('person.n.01').