Question: when were the first stones put up at stonehenge
[{'answer': 'between 2400 and 2200 BC', 'provenance': [{'wikipedia_id': '27633', 'title': 'Stonehenge', 'start_paragraph_id': 2, 'start_character': 267, 'end_paragraph_id': 2, 'end_character': 291, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '27633', 'title': 'Stonehenge', 'start_paragraph_id': 2, 'start_character': 0, 'end_paragraph_id': 2, 'end_character': 352, 'bleu_score': 0.9669306597086381, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 10313670228086708293}, 'section': 'Section::::Abstract.'}]}]