['vaccine', 'reach', 'EmptyParameter', 'EmptyParameter', 'EmptyParameter'] ['they', 'work', 'develop', 'EmptyParameter', 'EmptyParameter'] ['they', 'develop', 'EmptyParameter', 'EmptyParameter', 'EmptyParameter']
["Synset('antigen.n.01')", 'reach-51.8', 'EmptyParameter', 'EmptyParameter', 'EmptyParameter'] ['<PRP>', 'work-73.2', 'appear-48.1.1', 'EmptyParameter', 'EmptyParameter'] ['<PRP>', 'appear-48.1.1', 'EmptyParameter', 'EmptyParameter', 'EmptyParameter']
The vaccine they have been working to develop must reach there.
the Synset('antigen.n.01') <PRP> have been working to develop must reach there.