Question: when did the us begin to fight in vietnam
[{'answer': 'March 8 , 1965', 'provenance': [{'wikipedia_id': '8453309', 'title': 'Role of the United States in the Vietnam War', 'start_paragraph_id': 91, 'start_character': 133, 'end_paragraph_id': 91, 'end_character': 147, 'bleu_score': 1.0, 'section': 'Section::::Americanization.:Build-up.\n'}]}, {'provenance': [{'wikipedia_id': '8453309', 'title': 'Role of the United States in the Vietnam War', 'start_paragraph_id': 91, 'start_character': 0, 'end_paragraph_id': 91, 'end_character': 796, 'bleu_score': 0.706426303105671, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 2259702362844337421}, 'section': 'Section::::Americanization.:Build-up.\n'}]}]