[Louis] went to the park with his father, [Harold]. [Tracy] was trying to call her brother [Robert]. He was busy taking care of his son [John], so he did n't hear the phone ringing. [John] is going to be spending the weekend with his grandfather [Harold].
('Tracy', 'Louis')
[Tracy] was trying to call her brother [Robert]. He was busy taking care of his son [John], so he did n't hear the phone ringing. [John] is going to be spending the weekend with his grandfather [Harold]. [Louis] went to the park with his father, [Harold].
[{('Tracy', 'brother', 'Louis'): [('Tracy', 'brother', 'Robert'), ('Robert', 'brother', 'Louis')]}, {('Robert', 'brother', 'Louis'): [('Robert', 'father', 'Harold'), ('Harold', 'son', 'Louis')]}, {('Robert', 'father', 'Harold'): [('Robert', 'son', 'John'), ('John', 'grandfather', 'Harold')]}]
['brother', 'son', 'grandfather', 'son']