Question: what's it called when copper turns green
[{'answer': 'Verdigris', 'provenance': [{'wikipedia_id': '1389116', 'title': 'Verdigris', 'start_paragraph_id': 0, 'start_character': 0, 'end_paragraph_id': 0, 'end_character': 9, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '1389116', 'title': 'Verdigris', 'start_paragraph_id': 1, 'start_character': 0, 'end_paragraph_id': 1, 'end_character': 422, 'bleu_score': 0.8582141963112441, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 7292481111186871094}, 'section': 'Section::::Abstract.'}]}]