About the Authors

Chunlin Lu

Roles Conceptualization, Data curation, Formal analysis, Investigation, Methodology, Project administration, Resources, Software, Supervision, Validation, Writing – original draft, Writing – review & editing

lu_chunlin@163.com

Affiliation School of foreign languages, Baotou Teachers’ College, Baotou, China

Competing Interests

The authors have declared that no competing interests exist.