[Jeffrey] often goes out for lunch with his sister, [Cheryl]. [Rebecca] and [James] had a picnic at the park. They had sandwiches and salad. [Jeffrey] took a cab to the mall with his sister [Cheryl]. [Cheryl]'s sister [Rebecca] drove herself there.
('James', 'Cheryl')
[Rebecca] and [James] had a picnic at the park. They had sandwiches and salad. [Jeffrey] took a cab to the mall with his sister [Cheryl]. [Cheryl]'s sister [Rebecca] drove herself there. [Jeffrey] often goes out for lunch with his sister, [Cheryl].
[{('James', 'sister', 'Cheryl'): [('James', 'brother', 'Jeffrey'), ('Jeffrey', 'sister', 'Cheryl')]}, {('James', 'brother', 'Jeffrey'): [('James', 'sister', 'Rebecca'), ('Rebecca', 'brother', 'Jeffrey')]}, {('Rebecca', 'brother', 'Jeffrey'): [('Rebecca', 'sister', 'Cheryl'), ('Cheryl', 'brother', 'Jeffrey')]}]
['sister', 'sister', 'brother', 'sister']