Question: when does the football transfer window open in 2018
[{'answer': 'August 9', 'provenance': [{'wikipedia_id': '2607843', 'title': 'Transfer window', 'start_paragraph_id': 8, 'start_character': 115, 'end_paragraph_id': 8, 'end_character': 123, 'bleu_score': 1.0, 'section': 'Section::::Current schedules and exceptions.\n'}]}, {'provenance': [{'wikipedia_id': '2607843', 'title': 'Transfer window', 'start_paragraph_id': 8, 'start_character': 0, 'end_paragraph_id': 8, 'end_character': 411, 'bleu_score': 0.97451705556073, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 2152667366786253799}, 'section': 'Section::::Current schedules and exceptions.\n'}]}]