Question: when did panama canal zone became a us territory
[{'answer': 'May 4 , 1904', 'provenance': [{'wikipedia_id': '315787', 'title': 'Panama Canal Zone', 'start_paragraph_id': 13, 'start_character': 401, 'end_paragraph_id': 13, 'end_character': 413, 'bleu_score': 1.0, 'section': 'Section::::History.:Construction (1903–1914).\n'}]}, {'provenance': [{'wikipedia_id': '315787', 'title': 'Panama Canal Zone', 'start_paragraph_id': 13, 'start_character': 0, 'end_paragraph_id': 13, 'end_character': 673, 'bleu_score': 0.9152148163790931, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 3349225255395718974}, 'section': 'Section::::History.:Construction (1903–1914).\n'}]}]