Question: when was the us constitution signed into law
[{'answer': 'June 21 , 1788', 'provenance': [{'wikipedia_id': '31644', 'title': 'Constitution of the United States', 'start_paragraph_id': 33, 'start_character': 3, 'end_paragraph_id': 33, 'end_character': 17, 'bleu_score': 1.0, 'section': 'Section::::History.:1788 ratification.\n'}]}]