[Mary] does n't like having to babysit her younger brother, [Dennis]. [Mary] and her sister [Jennifer] played golf together. [Mary] won easily.
('Jennifer', 'Dennis')
[Mary] and her sister [Jennifer] played golf together. [Mary] won easily. [Mary] does n't like having to babysit her younger brother, [Dennis].
[{('Jennifer', 'brother', 'Dennis'): [('Jennifer', 'sister', 'Mary'), ('Mary', 'brother', 'Dennis')]}]
['sister', 'brother']