Question: what was the front line trench in ww1
[{'answer': 'Western Front', 'provenance': [{'wikipedia_id': '182259', 'title': 'Trench warfare', 'start_paragraph_id': 1, 'start_character': 270, 'end_paragraph_id': 1, 'end_character': 283, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '182259', 'title': 'Trench warfare', 'start_paragraph_id': 1, 'start_character': 0, 'end_paragraph_id': 1, 'end_character': 395, 'bleu_score': 0.8625766602352211, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 3215326924622371157}, 'section': 'Section::::Abstract.'}]}]