研一 英语怎么翻译？

研一:First-grade post-graduate
例句:“微笑志愿者”小组的学生负责人、研一学生徐晓红说，大家发现保持微笑并不是一件简单的事。
Xu Xiaohong, a first-grade post-graduate student at the university, leads the team. She said that not all students found it easy to smile all the time.

a first year graduate student 研一学生

year one for master degree