['it', 'require', 'EmptyParameter', 'they', 'of']
['<PRP>', 'require-103-1', 'EmptyParameter', '<PRP>', 'of']
Humans are capable of taking action when it is required of them.
Synset('primate.n.02') are Synset('capable.a.03') of taking Synset('physical_entity.n.01') when <PRP> is required of <PRP>.