Question: when did the us enter japan in ww2
[{'answer': '7 / 8 December 1941'}, {'provenance': [{'wikipedia_id': '342641', 'title': 'Pacific War', 'start_paragraph_id': 2, 'start_character': 0, 'end_paragraph_id': 2, 'end_character': 521, 'bleu_score': 0.881333417020795, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 3577564197390714009}, 'section': 'Section::::Abstract.'}]}]