[George] does not know he has a son named [Douglas]. [George] read a bedtime story to his daughter [Ann].
('Ann', 'Douglas')
[George] read a bedtime story to his daughter [Ann]. [George] does not know he has a son named [Douglas].
[{('Ann', 'brother', 'Douglas'): [('Ann', 'father', 'George'), ('George', 'son', 'Douglas')]}]
['father', 'son']