[Douglas] wanted to go to the bookstore with his grandfather, [Clarence], but [Douglas]'s brother, [Jerry], told him that [Clarence] wo n't be able to come today.
('Clarence', 'Jerry')
[Douglas] wanted to go to the bookstore with his grandfather, [Clarence], but [Douglas]'s brother, [Jerry], told him that [Clarence] wo n't be able to come today.
[{('Clarence', 'grandson', 'Jerry'): [('Clarence', 'grandson', 'Douglas'), ('Douglas', 'brother', 'Jerry')]}]
['grandson', 'brother']