Question: a famous feature of the national theatre's olivier stage is its
[{'answer': 'drum revolve', 'provenance': [{'wikipedia_id': '167775', 'title': 'Royal National Theatre', 'start_paragraph_id': 18, 'start_character': 230, 'end_paragraph_id': 18, 'end_character': 242, 'bleu_score': 1.0, 'section': 'Section::::Theatre building and architecture.:Theatres.:Olivier Theatre.\n'}]}, {'provenance': [{'wikipedia_id': '167775', 'title': 'Royal National Theatre', 'start_paragraph_id': 18, 'start_character': 0, 'end_paragraph_id': 18, 'end_character': 917, 'bleu_score': 0.986969988197764, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 4071498012161366901}, 'section': 'Section::::Theatre building and architecture.:Theatres.:Olivier Theatre.\n'}]}]