[Harold] threw the ball to his son [Pedro]. [Harold] did n't like playing ball with his daughter [Marie]. [Marie] and her husband [Robert] just got back from their honeymoon in Hawaii. They had a wonderful time there. [Mario]'s father [Robert] is going to coach the team this year.
('Pedro', 'Mario')
[Harold] threw the ball to his son [Pedro]. [Harold] did n't like playing ball with his daughter [Marie]. [Marie] and her husband [Robert] just got back from their honeymoon in Hawaii. They had a wonderful time there. [Mario]'s father [Robert] is going to coach the team this year.
[{('Pedro', 'nephew', 'Mario'): [('Pedro', 'sister', 'Marie'), ('Marie', 'son', 'Mario')]}, {('Pedro', 'sister', 'Marie'): [('Pedro', 'father', 'Harold'), ('Harold', 'daughter', 'Marie')]}, {('Marie', 'son', 'Mario'): [('Marie', 'husband', 'Robert'), ('Robert', 'son', 'Mario')]}]
['father', 'daughter', 'husband', 'son']