Question: where does combustion take place in a furnace
[{'answer': 'firebox', 'provenance': [{'wikipedia_id': '238150', 'title': 'Furnace', 'start_paragraph_id': 50, 'start_character': 421, 'end_paragraph_id': 50, 'end_character': 428, 'bleu_score': 1.0, 'section': 'Section::::Industrial furnaces.\n'}]}, {'provenance': [{'wikipedia_id': '238150', 'title': 'Furnace', 'start_paragraph_id': 50, 'start_character': 0, 'end_paragraph_id': 50, 'end_character': 559, 'bleu_score': 0.9804854598160591, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 60674609879280943}, 'section': 'Section::::Industrial furnaces.\n'}]}]