Question: when did the us enter world war 1
[{'answer': 'April 1917', 'provenance': [{'wikipedia_id': '25162935', 'title': 'American entry into World War I', 'start_paragraph_id': 1, 'start_character': 44, 'end_paragraph_id': 1, 'end_character': 54, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '25162935', 'title': 'American entry into World War I', 'start_paragraph_id': 2, 'start_character': 0, 'end_paragraph_id': 2, 'end_character': 685, 'bleu_score': 0.699541673772138, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 9559917072376751775}, 'section': 'Section::::Abstract.'}]}]