Question: the capital of the tang dynasty and the largest city in the world at the time was
[{'answer': "Chang'an", 'provenance': [{'wikipedia_id': '43455', 'title': 'Tang dynasty', 'start_paragraph_id': 1, 'start_character': 507, 'end_paragraph_id': 1, 'end_character': 515, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '43455', 'title': 'Tang dynasty', 'start_paragraph_id': 1, 'start_character': 107, 'end_paragraph_id': 1, 'end_character': 582, 'bleu_score': 0.7017345107596641, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 1915364348120843250}, 'section': 'Section::::Abstract.'}]}]