[Ronald] always looked up to his brother [Mario]. [Lizzie] invited her father [Robert] to dinner. [Lizzie] likes to stay with her grandfather [Harold] during the summer because he has a pool in his back yard. [Robert] has a son named [Mario] that looks exactly like him.
('Ronald', 'Harold')
[Ronald] always looked up to his brother [Mario]. [Robert] has a son named [Mario] that looks exactly like him. [Lizzie] invited her father [Robert] to dinner. [Lizzie] likes to stay with her grandfather [Harold] during the summer because he has a pool in his back yard.
[{('Ronald', 'grandfather', 'Harold'): [('Ronald', 'sister', 'Lizzie'), ('Lizzie', 'grandfather', 'Harold')]}, {('Ronald', 'sister', 'Lizzie'): [('Ronald', 'father', 'Robert'), ('Robert', 'daughter', 'Lizzie')]}, {('Ronald', 'father', 'Robert'): [('Ronald', 'brother', 'Mario'), ('Mario', 'father', 'Robert')]}]
['brother', 'father', 'daughter', 'grandfather']