[Amy] took her younger sister [Theresa] to the carnival last weekend. [George] and his sister [Theresa] went to the ice skating rink. [George] fell down and [Theresa] laughed at him.
('George', 'Amy')
[George] and his sister [Theresa] went to the ice skating rink. [George] fell down and [Theresa] laughed at him. [Amy] took her younger sister [Theresa] to the carnival last weekend.
[{('George', 'sister', 'Amy'): [('George', 'sister', 'Theresa'), ('Theresa', 'sister', 'Amy')]}]
['sister', 'sister']