Question: when was chlorine first added to drinking water in the uk
[{'answer': '1897', 'provenance': [{'wikipedia_id': '38840679', 'title': 'Water chlorination', 'start_paragraph_id': 3, 'start_character': 317, 'end_paragraph_id': 3, 'end_character': 321, 'bleu_score': 1.0, 'section': 'Section::::History.\n'}]}, {'provenance': [{'wikipedia_id': '38840679', 'title': 'Water chlorination', 'start_paragraph_id': 3, 'start_character': 0, 'end_paragraph_id': 3, 'end_character': 420, 'bleu_score': 0.9383908431221111, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 10371985987833601746}, 'section': 'Section::::History.\n'}]}]