[Aaron] and his sister [Erika] called their mom [Tracy] for her birthday. [Aaron]'s sister [Bettie] did not call. [Tracy] was so glad to travel with her son, [Bobby]. He made the trip enjoyable.
('Bobby', 'Bettie')
[Tracy] was so glad to travel with her son, [Bobby]. He made the trip enjoyable. [Aaron] and his sister [Erika] called their mom [Tracy] for her birthday. [Aaron]'s sister [Bettie] did not call.
[{('Bobby', 'sister', 'Bettie'): [('Bobby', 'mother', 'Tracy'), ('Tracy', 'daughter', 'Bettie')]}, {('Tracy', 'daughter', 'Bettie'): [('Tracy', 'son', 'Aaron'), ('Aaron', 'sister', 'Bettie')]}, {('Tracy', 'son', 'Aaron'): [('Tracy', 'daughter', 'Erika'), ('Erika', 'brother', 'Aaron')]}]
['mother', 'daughter', 'brother', 'sister']