Question: when did the battles of lexington and concord happen
[{'answer': 'April 19 , 1775', 'provenance': [{'wikipedia_id': '4321886', 'title': 'Battles of Lexington and Concord', 'start_paragraph_id': 36, 'start_character': 180, 'end_paragraph_id': 36, 'end_character': 195, 'bleu_score': 1.0, 'section': 'Section::::The Battles.:Lexington.\n'}]}, {'provenance': [{'wikipedia_id': '4321886', 'title': 'Battles of Lexington and Concord', 'start_paragraph_id': 1, 'start_character': 0, 'end_paragraph_id': 1, 'end_character': 416, 'bleu_score': 0.9684940092844061, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 3379417628856700023}, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '4321886', 'title': 'Battles of Lexington and Concord', 'section': 'Section::::The Battles.:Lexington.\n', 'start_paragraph_id': 36, 'end_paragraph_id': 36, 'meta': {'evidence_span': ["Although often styled a battle, in reality the engagement at Lexington was a minor brush or skirmish. As the regulars' advance guard under Pitcairn entered Lexington at sunrise on April 19, 1775, about 80 Lexington militiamen emerged from Buckman Tavern and stood in ranks on the village common watching them, and between 40 and 100 spectators watched from along the side of the road.", "As the regulars' advance guard under Pitcairn entered Lexington at sunrise on April 19, 1775, about 80 Lexington militiamen emerged from Buckman Tavern and stood in ranks on the village common watching them, and between 40 and 100 spectators watched from along the side of the road.", "ton, seven Munroe (including the company's orderly sergeant, William Munroe), four Parker, three Tidd, three Locke, and three Reed; fully one quarter of them were related to Captain Parker in some way. This group of"]}}]}]