[Martha]'s brother [Chris] took her to the fair when she was little. [Chris] also brought his brother [Charles]. [Charles] and his mother [Lena] went to the animal shelter to adopt a cat.
('Martha', 'Lena')
[Martha]'s brother [Chris] took her to the fair when she was little. [Chris] also brought his brother [Charles]. [Charles] and his mother [Lena] went to the animal shelter to adopt a cat.
[{('Martha', 'mother', 'Lena'): [('Martha', 'brother', 'Chris'), ('Chris', 'mother', 'Lena')]}, {('Chris', 'mother', 'Lena'): [('Chris', 'brother', 'Charles'), ('Charles', 'mother', 'Lena')]}]
['brother', 'brother', 'mother']