Question: what type of government structure does the us have
[{'answer': 'constitutional republic', 'provenance': [{'wikipedia_id': '12229', 'title': 'Government', 'start_paragraph_id': 20, 'start_character': 86, 'end_paragraph_id': 20, 'end_character': 109, 'bleu_score': 1.0, 'section': 'Section::::Political science.:Classifying government.\n'}]}]