Question: what was the official beginning of world war ii in europe
[{'answer': '1 September 1939', 'provenance': [{'wikipedia_id': '32927', 'title': 'World War II', 'start_paragraph_id': 2, 'start_character': 183, 'end_paragraph_id': 2, 'end_character': 199, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '32927', 'title': 'World War II', 'start_paragraph_id': 7, 'start_character': 0, 'end_paragraph_id': 7, 'end_character': 368, 'bleu_score': 0.9318557434050331, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 9500605097148083993}, 'section': 'Section::::Chronology.\n'}]}]