[Jennifer] and her brother [Dennis] watched TV together. [Milton] was invited to watch too, because [Jennifer] is his sister.
('Milton', 'Dennis')
[Jennifer] and her brother [Dennis] watched TV together. [Milton] was invited to watch too, because [Jennifer] is his sister.
[{('Milton', 'brother', 'Dennis'): [('Milton', 'sister', 'Jennifer'), ('Jennifer', 'brother', 'Dennis')]}]
['sister', 'brother']