['they', 'find', 'debris', 'EmptyParameter', 'EmptyParameter']
['<PRP>', 'declare-29.4-1-1-2', "Synset('waste.n.01')", 'EmptyParameter', 'EmptyParameter']
They find a lot of debris blocking their way.
<PRP> find a Synset('geographical_area.n.01') of Synset('waste.n.01') blocking <PRP> Synset('assets.n.01').