Question: when did alcohol become illegal in the united states
[{'answer': '1920', 'provenance': [{'wikipedia_id': '22418955', 'title': 'Prohibition in the United States', 'start_paragraph_id': 1, 'start_character': 154, 'end_paragraph_id': 1, 'end_character': 158, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '22418955', 'title': 'Prohibition in the United States', 'start_paragraph_id': 1, 'start_character': 0, 'end_paragraph_id': 1, 'end_character': 166, 'bleu_score': 0.9181891462193901, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 7203237458828373145}, 'section': 'Section::::Abstract.'}]}]