Question: when did horses start being used by humans
[{'answer': 'approximately 3500 BCE', 'provenance': [{'wikipedia_id': '53543', 'title': 'Domestication of the horse', 'start_paragraph_id': 2, 'start_character': 288, 'end_paragraph_id': 2, 'end_character': 310, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '53543', 'title': 'Domestication of the horse', 'start_paragraph_id': 2, 'start_character': 0, 'end_paragraph_id': 2, 'end_character': 494, 'bleu_score': 0.5595267838349981, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 1125049259960216144}, 'section': 'Section::::Abstract.'}]}]