[William] bought a book for his father [Jacob]. [Mary] asked her son [Jacob] to help her fix her television.
('Mary', 'William')
[Mary] asked her son [Jacob] to help her fix her television. [William] bought a book for his father [Jacob].
[{('Mary', 'grandson', 'William'): [('Mary', 'son', 'Jacob'), ('Jacob', 'son', 'William')]}]