Question: the depth of the wave base is approximately
[{'answer': 'half the wavelength', 'provenance': [{'wikipedia_id': '869994', 'title': 'Wave base', 'start_paragraph_id': 3, 'start_character': 276, 'end_paragraph_id': 3, 'end_character': 295, 'bleu_score': 1.0, 'section': 'Section::::Process.\n'}]}, {'provenance': [{'wikipedia_id': '869994', 'title': 'Wave base', 'start_paragraph_id': 3, 'start_character': 0, 'end_paragraph_id': 3, 'end_character': 295, 'bleu_score': 0.9611463610973231, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 10086163411778320027}, 'section': 'Section::::Process.\n'}]}]