[Harold] favored his son [Robert] over his other son [Pedro]. [Tracy] told her daughter [Laura] to wash up. Dinner was ready. [Robert] has a brother who is younger than him. The brother has a sister whose name is [Tracy].
('Pedro', 'Laura')
[Harold] favored his son [Robert] over his other son [Pedro]. [Robert] has a brother who is younger than him. The brother has a sister whose name is [Tracy]. [Tracy] told her daughter [Laura] to wash up. Dinner was ready.
[{('Pedro', 'niece', 'Laura'): [('Pedro', 'sister', 'Tracy'), ('Tracy', 'daughter', 'Laura')]}, {('Pedro', 'sister', 'Tracy'): [('Pedro', 'father', 'Harold'), ('Harold', 'daughter', 'Tracy')]}, {('Harold', 'daughter', 'Tracy'): [('Harold', 'son', 'Robert'), ('Robert', 'sister', 'Tracy')]}]
['father', 'son', 'sister', 'daughter']