[Pamela] was mad at her brother [Charles], because [Charles] had called her fat. [Charles] received some birthday money from his grandmother [Frances]. [Pamela] took her younger sister [Martha] to the carnival last weekend.
('Martha', 'Frances')
[Pamela] took her younger sister [Martha] to the carnival last weekend. [Pamela] was mad at her brother [Charles], because [Charles] had called her fat. [Charles] received some birthday money from his grandmother [Frances].
[{('Martha', 'grandmother', 'Frances'): [('Martha', 'sister', 'Pamela'), ('Pamela', 'grandmother', 'Frances')]}, {('Pamela', 'grandmother', 'Frances'): [('Pamela', 'brother', 'Charles'), ('Charles', 'grandmother', 'Frances')]}]
['sister', 'brother', 'grandmother']