Question: when did the sumerians emerge as a civilization
[{'answer': 'c. 5500 and 4000 BC', 'provenance': [{'wikipedia_id': '50521', 'title': 'Sumer', 'start_paragraph_id': 6, 'start_character': 80, 'end_paragraph_id': 6, 'end_character': 99, 'bleu_score': 1.0, 'section': 'Section::::Origins.\n'}]}, {'provenance': [{'wikipedia_id': '50521', 'title': 'Sumer', 'start_paragraph_id': 8, 'start_character': 0, 'end_paragraph_id': 8, 'end_character': 462, 'bleu_score': 0.505294239664661, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 11116763020961470844}, 'section': 'Section::::Origins.\n'}]}]