Question: when did the first plane break the sound barrier
[{'answer': 'April 1944', 'provenance': [{'wikipedia_id': '166072', 'title': 'Sound barrier', 'start_paragraph_id': 14, 'start_character': 204, 'end_paragraph_id': 14, 'end_character': 214, 'bleu_score': 1.0, 'section': 'Section::::History.:Early claims.\n'}]}, {'provenance': [{'wikipedia_id': '166072', 'title': 'Sound barrier', 'start_paragraph_id': 14, 'start_character': 0, 'end_paragraph_id': 14, 'end_character': 601, 'bleu_score': 0.9536330554540541, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 2174766470242197}, 'section': 'Section::::History.:Early claims.\n'}]}]