I use OpenNLP to parser some medical report but one of the Parser tree result draw my attention. The original line is as follow:
"They are replaced by tumour tissue, which show glandular differentiation."
The Parser tree is looks like this
(TOP (S (NP (PRP They)) (VP (VBP are) (VP (VBN replaced) (PP (IN by)
(NP (NP (JJ tumour) (NN tissue,)) (SBAR (WHNP (WDT which))
(S (VP (VBP show) (NP (JJ glandular))))))))) (. differentiation.) ))
The thing that I don't get it is the (. differentiation.), as I know the "." is mean sentence closer. But as you can see there's word 'differentiation', so what is the meaning of that? I know that it's a NN but what can I do to ask OpenNLP to process that? Do I need to provide my own information and train the system for this?