Question: when did the cultural revolution start and end in china
[{'answer': '1966', 'provenance': [{'wikipedia_id': '45311', 'title': 'Cultural Revolution', 'start_paragraph_id': 1, 'start_character': 121, 'end_paragraph_id': 1, 'end_character': 125, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'answer': '1976', 'provenance': [{'wikipedia_id': '45311', 'title': 'Cultural Revolution', 'start_paragraph_id': 1, 'start_character': 132, 'end_paragraph_id': 1, 'end_character': 136, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '45311', 'title': 'Cultural Revolution', 'start_paragraph_id': 1, 'start_character': 0, 'end_paragraph_id': 1, 'end_character': 663, 'bleu_score': 0.606826667820608, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 14677279273509907300}, 'section': 'Section::::Abstract.'}]}]