story: [Dan] and his brother [Vincent] are going to visit [Vincent]'s grandfather [Jason] at the hospital.
query: ('Dan', 'Jason')
clean_story: [Dan] and his brother [Vincent] are going to visit [Vincent]'s grandfather [Jason] at the hospital.
proof_state: [{('Dan', 'grandfather', 'Jason'): [('Dan', 'brother', 'Vincent'), ('Vincent', 'grandfather', 'Jason')]}]