['he', 'turn', 'back', 'they', 'EmptyParameter']
['<PRP>', 'turn-26.6.1-1', "Synset('covering.n.02')", '<PRP>', 'EmptyParameter']
He curtly turns his back on both of them.
<PRP> curtly turns <PRP> Synset('covering.n.02') on both of <PRP>.