Question: when were freezers combined with refrigerators and sold on the market
[{'answer': '1940', 'provenance': [{'wikipedia_id': '1036259', 'title': 'Refrigerator', 'start_paragraph_id': 2, 'start_character': 574, 'end_paragraph_id': 2, 'end_character': 578, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '1036259', 'title': 'Refrigerator', 'start_paragraph_id': 2, 'start_character': 0, 'end_paragraph_id': 2, 'end_character': 638, 'bleu_score': 0.9536330554540541, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 4520853892098201844}, 'section': 'Section::::Abstract.'}]}]