Question: when did the song dynasty start and end
[{'answer': '960 -- 1279'}, {'provenance': [{'wikipedia_id': '56978', 'title': 'Song dynasty', 'start_paragraph_id': 1, 'start_character': 0, 'end_paragraph_id': 1, 'end_character': 723, 'bleu_score': 0.75003234131133, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 17920590514382906993}, 'section': 'Section::::Abstract.'}]}]