[Tracy]'s father, [Harold], took her to the park to play catch. [Harold]'s son, [Pedro], wanted to play too so he went with them. [Robert]'s sister [Tracy] went as well and bought everyone ice cream. [Pedro] called his brother [Antonio] on Friday because it was his birthday.
('Robert', 'Antonio')
[Tracy]'s father, [Harold], took her to the park to play catch. [Harold]'s son, [Pedro], wanted to play too so he went with them. [Robert]'s sister [Tracy] went as well and bought everyone ice cream. [Pedro] called his brother [Antonio] on Friday because it was his birthday.
[{('Robert', 'brother', 'Antonio'): [('Robert', 'father', 'Harold'), ('Harold', 'son', 'Antonio')]}, {('Robert', 'father', 'Harold'): [('Robert', 'sister', 'Tracy'), ('Tracy', 'father', 'Harold')]}, {('Harold', 'son', 'Antonio'): [('Harold', 'son', 'Pedro'), ('Pedro', 'brother', 'Antonio')]}]
['sister', 'father', 'son', 'brother']