[Robert] and his wife [Marie] went rock-climbing this weekend. [Beverly] and her sister [Dorothy] are planning a surprise birthday party for [Harold], [Dorothy]'s father. [Beverly] and her sister [Marie] braided each other's hair before school.
('Robert', 'Harold')
[Robert] and his wife [Marie] went rock-climbing this weekend. [Beverly] and her sister [Marie] braided each other's hair before school. [Beverly] and her sister [Dorothy] are planning a surprise birthday party for [Harold], [Dorothy]'s father.
[{('Robert', 'father-in-law', 'Harold'): [('Robert', 'wife', 'Marie'), ('Marie', 'father', 'Harold')]}, {('Marie', 'father', 'Harold'): [('Marie', 'sister', 'Dorothy'), ('Dorothy', 'father', 'Harold')]}, {('Marie', 'sister', 'Dorothy'): [('Marie', 'sister', 'Beverly'), ('Beverly', 'sister', 'Dorothy')]}]
['wife', 'sister', 'sister', 'father']