Question: knot is measure to known the speed of
[{'answer': 'nautical miles per hour', 'provenance': [{'wikipedia_id': '28748', 'title': 'Speed', 'start_paragraph_id': 34, 'start_character': 19, 'end_paragraph_id': 34, 'end_character': 42, 'bleu_score': 1.0, 'section': 'Section::::Units.\n'}]}, {'provenance': [{'wikipedia_id': '28748', 'title': 'Speed', 'start_paragraph_id': 34, 'start_character': 0, 'end_paragraph_id': 34, 'end_character': 59, 'bleu_score': 0.7860753021519781, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 9395402439002861111}, 'section': 'Section::::Units.\n'}]}]