Question: when was the first jet plane used in war
[{'answer': 'World War II', 'provenance': [{'wikipedia_id': '885501', 'title': 'List of jet aircraft of World War II', 'start_paragraph_id': 0, 'start_character': 24, 'end_paragraph_id': 0, 'end_character': 36, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '885501', 'title': 'List of jet aircraft of World War II', 'start_paragraph_id': 1, 'start_character': 0, 'end_paragraph_id': 1, 'end_character': 920, 'bleu_score': 0.943914004839392, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 12567915910385033184}, 'section': 'Section::::Abstract.'}]}]