[Milton] went skiing with his brother [Dennis]. [Dennis]'s sister [Jennifer] watched from the ski lodge.
('Jennifer', 'Milton')
[Milton] went skiing with his brother [Dennis]. [Dennis]'s sister [Jennifer] watched from the ski lodge.
[{('Jennifer', 'brother', 'Milton'): [('Jennifer', 'brother', 'Dennis'), ('Dennis', 'brother', 'Milton')]}]
['brother', 'brother']