[Douglas]'s sister, [Ann], participated in the dance contest. [Douglas] and [Jerry] are brothers who look nothing alike.
('Jerry', 'Ann')
[Douglas] and [Jerry] are brothers who look nothing alike. [Douglas]'s sister, [Ann], participated in the dance contest.
[{('Jerry', 'sister', 'Ann'): [('Jerry', 'brother', 'Douglas'), ('Douglas', 'sister', 'Ann')]}]
['brother', 'sister']