Question: when did the first world war started and ended
[{'answer': '28 July 1914', 'provenance': [{'wikipedia_id': '4764461', 'title': 'World War I', 'start_paragraph_id': 1, 'start_character': 155, 'end_paragraph_id': 1, 'end_character': 167, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'answer': '11 November 1918', 'provenance': [{'wikipedia_id': '4764461', 'title': 'World War I', 'start_paragraph_id': 1, 'start_character': 171, 'end_paragraph_id': 1, 'end_character': 187, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}]