Question: what cities have been capital of the united states
[{'answer': 'New York City', 'provenance': [{'wikipedia_id': '31979', 'title': 'United States Capitol', 'start_paragraph_id': 5, 'start_character': 175, 'end_paragraph_id': 5, 'end_character': 188, 'bleu_score': 1.0, 'section': 'Section::::History.:Background.\n'}]}, {'answer': 'Philadelphia', 'provenance': [{'wikipedia_id': '31979', 'title': 'United States Capitol', 'start_paragraph_id': 5, 'start_character': 123, 'end_paragraph_id': 5, 'end_character': 135, 'bleu_score': 1.0, 'section': 'Section::::History.:Background.\n'}]}, {'answer': 'Washington , D.C.', 'provenance': [{'wikipedia_id': '31979', 'title': 'United States Capitol', 'start_paragraph_id': 46, 'start_character': 404, 'end_paragraph_id': 46, 'end_character': 423, 'bleu_score': 1.0, 'section': 'Section::::Interior.:Crypt.\n'}]}, {'provenance': [{'wikipedia_id': '31979', 'title': 'United States Capitol', 'start_paragraph_id': 7, 'start_character': 0, 'end_paragraph_id': 7, 'end_character': 747, 'bleu_score': 0.9705733906555171, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 3750683199937609294}, 'section': 'Section::::History.:Background.\n'}]}]