story: [Michael] was happy to step onto the football pitch with his brother, [Alan]. As they played football, their sister, [Marian], watched from the sidelines with her son, [Mark].
query: ('Alan', 'Mark')
clean_story: [Michael] was happy to step onto the football pitch with his brother, [Alan]. As they played football, their sister, [Marian], watched from the sidelines with her son, [Mark].
proof_state: [{('Alan', 'nephew', 'Mark'): [('Alan', 'sister', 'Marian'), ('Marian', 'son', 'Mark')]}, {('Alan', 'sister', 'Marian'): [('Alan', 'brother', 'Michael'), ('Michael', 'sister', 'Marian')]}]