show flights from baltimore to san francisco between 6 pm and 8 pm on friday
O O O B-fromloc.city_name O B-toloc.city_name I-toloc.city_name O B-depart_time.start_time I-depart_time.start_time O B-depart_time.end_time I-depart_time.end_time O B-depart_date.day_name