[Martha] went on a vacation with her brother [Chris]. [Charles] and her sister [Pamela] decided to take a trip to Mexico together. [Pamela] is one of my favorite students. She is the younger sister of [Chris], who I taught last year,
('Martha', 'Charles')
[Martha] went on a vacation with her brother [Chris]. [Pamela] is one of my favorite students. She is the younger sister of [Chris], who I taught last year, [Charles] and her sister [Pamela] decided to take a trip to Mexico together.
[{('Martha', 'brother', 'Charles'): [('Martha', 'brother', 'Chris'), ('Chris', 'brother', 'Charles')]}, {('Chris', 'brother', 'Charles'): [('Chris', 'sister', 'Pamela'), ('Pamela', 'brother', 'Charles')]}]
['brother', 'sister', 'brother']