[Roy] watched his daughter [Lois] playing basketball. [Lois] threw the ball to her brother [John] who made the basket.
('Roy', 'John')
[Roy] watched his daughter [Lois] playing basketball. [Lois] threw the ball to her brother [John] who made the basket.
[{('Roy', 'son', 'John'): [('Roy', 'daughter', 'Lois'), ('Lois', 'brother', 'John')]}]