if something is lost in something else, then that something else contains that something
separated_thing is divided_thing. lost_river is tangible_thing. separated_thing is not divided_thing. find_inside is not things. stealing_storage_space is unnatural_thing. storage is not somewhere_to_put_things. space is not what_between_else. stealing_storage_space is not unnatural_thing. lost_river is not tangible_thing. storage is somewhere_to_put_things.