[Heather] was celebrating her birthday with her mother [Dorothy]. [Dorothy] is taking a trip to see her sister [Tracy]. [Marie] and her sister [Tracy] are the only children in their family. [Heather] and her sister [Rebecca] are the only children in their family.
('Rebecca', 'Marie')
[Heather] and her sister [Rebecca] are the only children in their family. [Heather] was celebrating her birthday with her mother [Dorothy]. [Dorothy] is taking a trip to see her sister [Tracy]. [Marie] and her sister [Tracy] are the only children in their family.
[{('Rebecca', 'aunt', 'Marie'): [('Rebecca', 'mother', 'Dorothy'), ('Dorothy', 'sister', 'Marie')]}, {('Rebecca', 'mother', 'Dorothy'): [('Rebecca', 'sister', 'Heather'), ('Heather', 'mother', 'Dorothy')]}, {('Dorothy', 'sister', 'Marie'): [('Dorothy', 'sister', 'Tracy'), ('Tracy', 'sister', 'Marie')]}]
['sister', 'mother', 'sister', 'sister']