Question: when did we start to use bc and ad
[{'answer': 'in 525', 'provenance': [{'wikipedia_id': '1400', 'title': 'Anno Domini', 'start_paragraph_id': 2, 'start_character': 340, 'end_paragraph_id': 2, 'end_character': 346, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '1400', 'title': 'Anno Domini', 'start_paragraph_id': 7, 'start_character': 0, 'end_paragraph_id': 7, 'end_character': 1063, 'bleu_score': 0.988857503993915, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 1162125246230189455}, 'section': 'Section::::History.\n'}]}]