[Pamela] called [Martha], her sister, to see if she wanted to go out to eat. [Martha] and her sister [Mildred] braided each other's hair before school. [Pamela] was watching TV with her grandfather [James].
('Mildred', 'James')
[Martha] and her sister [Mildred] braided each other's hair before school. [Pamela] called [Martha], her sister, to see if she wanted to go out to eat. [Pamela] was watching TV with her grandfather [James].
[{('Mildred', 'grandfather', 'James'): [('Mildred', 'sister', 'Martha'), ('Martha', 'grandfather', 'James')]}, {('Martha', 'grandfather', 'James'): [('Martha', 'sister', 'Pamela'), ('Pamela', 'grandfather', 'James')]}]
['sister', 'sister', 'grandfather']