Question: when was the sound barrier broken for the first time
[{'answer': '1947', 'provenance': [{'wikipedia_id': '6185', 'title': 'Chuck Yeager', 'start_paragraph_id': 1, 'start_character': 129, 'end_paragraph_id': 1, 'end_character': 133, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '6185', 'title': 'Chuck Yeager', 'start_paragraph_id': 1, 'start_character': 0, 'end_paragraph_id': 1, 'end_character': 222, 'bleu_score': 0.6752100096808611, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 6250716405192442301}, 'section': 'Section::::Abstract.'}]}]