Question: the twelve-bar blues and the aaba are examples of
[{'answer': 'chord progressions', 'provenance': [{'wikipedia_id': '30603', 'title': 'Twelve-bar blues', 'start_paragraph_id': 1, 'start_character': 69, 'end_paragraph_id': 1, 'end_character': 87, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '30603', 'title': 'Twelve-bar blues', 'start_paragraph_id': 1, 'start_character': 0, 'end_paragraph_id': 1, 'end_character': 281, 'bleu_score': 0.9603762111511761, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 18238021861642070362}, 'section': 'Section::::Abstract.'}]}]