story: [Nancy] needed to go to the store. [Nancy] asked her sister [Crystal] for a ride. [Melissa] was sewing a sweater for her sister [Crystal]. [Otto] and his sister [Crystal] got their mother [Crystal] a new computer for her birthday. She really liked it.
query: ('Otto', 'Nancy')
clean_story: [Otto] and his sister [Crystal] got their mother [Crystal] a new computer for her birthday. She really liked it. [Nancy] needed to go to the store. [Nancy] asked her sister [Crystal] for a ride.
proof_state: [{('Otto', 'sister', 'Nancy'): [('Otto', 'sister', 'Crystal'), ('Crystal', 'sister', 'Nancy')]}]