[Robert] bought a book for his son [Allan]. [Allan] was having a cookout one day, and invited his sister [Angelica]. [Angelica]'s brother [Ronald] drove them to the cookout. [Ronald] and [Elsie] celebrated their one year anniversary of marriage today.
('Elsie', 'Robert')
[Ronald] and [Elsie] celebrated their one year anniversary of marriage today. [Allan] was having a cookout one day, and invited his sister [Angelica]. [Angelica]'s brother [Ronald] drove them to the cookout. [Robert] bought a book for his son [Allan].
[{('Elsie', 'father-in-law', 'Robert'): [('Elsie', 'husband', 'Ronald'), ('Ronald', 'father', 'Robert')]}, {('Ronald', 'father', 'Robert'): [('Ronald', 'sister', 'Angelica'), ('Angelica', 'father', 'Robert')]}, {('Angelica', 'father', 'Robert'): [('Angelica', 'brother', 'Allan'), ('Allan', 'father', 'Robert')]}]
['husband', 'sister', 'brother', 'father']