Question: when was the last time boston won the world series
[{'answer': '2013', 'provenance': [{'wikipedia_id': '4339', 'title': 'Boston Red Sox', 'start_paragraph_id': 3, 'start_character': 321, 'end_paragraph_id': 3, 'end_character': 325, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}]