Question: when did the zhou dynasty overthrew the shang
[{'answer': '1046 BC', 'provenance': [{'wikipedia_id': '43465', 'title': 'Shang dynasty', 'start_paragraph_id': 1, 'start_character': 602, 'end_paragraph_id': 1, 'end_character': 609, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}]