[Clarence] was upset at his daughter [Lillian] for staying out so late. [Lillian] bought her son [John] a basketball for his birthday.
('John', 'Clarence')
[Lillian] bought her son [John] a basketball for his birthday. [Clarence] was upset at his daughter [Lillian] for staying out so late.
[{('John', 'grandfather', 'Clarence'): [('John', 'mother', 'Lillian'), ('Lillian', 'father', 'Clarence')]}]
['mother', 'father']