She joined the student council during her sophomore year at college.

sophomore 是名词，指大学或高中的"二年级学生"。这个词由希腊语词根 sophos（聪明的）和 moros（愚蠢的）组合而成，字面意思是"半聪明半愚蠢"，用来形容处于大学中间阶段的学生状态。