['they', 'have', 'fly', 'EmptyParameter', 'EmptyParameter'] ['they', 'fly', 'prolong', 'search', 'EmptyParameter']
['<PRP>', 'own-100', 'run-51.3.2', 'EmptyParameter', 'EmptyParameter'] ['<PRP>', 'run-51.3.2', 'sustain-55.6', "Synset('act.n.02')", 'EmptyParameter']
They have to fly very low to not be detected, prolonging their search.
<PRP> have to fly very Synset('low.a.05') to not be detected, prolonging <PRP> Synset('act.n.02').