Question: during which type of stretching does viscoelastic creep occur
[{'answer': 'a step constant stress', 'provenance': [{'wikipedia_id': '711288', 'title': 'Viscoelasticity', 'start_paragraph_id': 85, 'start_character': 18, 'end_paragraph_id': 85, 'end_character': 40, 'bleu_score': 1.0, 'section': 'Section::::Viscoelastic creep.\n'}]}, {'provenance': [{'wikipedia_id': '711288', 'title': 'Viscoelasticity', 'start_paragraph_id': 85, 'start_character': 0, 'end_paragraph_id': 85, 'end_character': 159, 'bleu_score': 0.9146912192286941, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 13915505368812461973}, 'section': 'Section::::Viscoelastic creep.\n'}]}]