Question: what is the system of measurement used in the us
[{'answer': 'United States customary units', 'provenance': [{'wikipedia_id': '32308', 'title': 'United States customary units', 'start_paragraph_id': 0, 'start_character': 0, 'end_paragraph_id': 0, 'end_character': 29, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '32308', 'title': 'United States customary units', 'start_paragraph_id': 1, 'start_character': 0, 'end_paragraph_id': 1, 'end_character': 545, 'bleu_score': 0.812782547921537, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 9404600014047173711}, 'section': 'Section::::Abstract.'}]}]