Question: what did the ancient romans build to maintain the supply of water in their cities
[{'answer': 'aqueducts', 'provenance': [{'wikipedia_id': '3745201', 'title': 'Roman aqueduct', 'start_paragraph_id': 1, 'start_character': 23, 'end_paragraph_id': 1, 'end_character': 32, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}]