[Joshua] and his brother [Hugh] went to the park. They threw a ball around and played with their dog. [Frances] played catch with her grandson [Clarence]. [Clarence]'s father [Joshua] was busy at work and could n't join them.
('Hugh', 'Frances')
[Joshua] and his brother [Hugh] went to the park. They threw a ball around and played with their dog. [Frances] played catch with her grandson [Clarence]. [Clarence]'s father [Joshua] was busy at work and could n't join them.
[{('Hugh', 'mother', 'Frances'): [('Hugh', 'brother', 'Joshua'), ('Joshua', 'mother', 'Frances')]}, {('Joshua', 'mother', 'Frances'): [('Joshua', 'son', 'Clarence'), ('Clarence', 'grandmother', 'Frances')]}]
['brother', 'son', 'grandmother']