Question: what is the standard unit of length in the si system
[{'answer': 'metre', 'provenance': [{'wikipedia_id': '26764', 'title': 'International System of Units', 'start_paragraph_id': 1, 'start_character': 266, 'end_paragraph_id': 1, 'end_character': 271, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}]