Since my Sophomore year, I have worked as a part-time tour guide in two travel agencies during summer holidays, Labor Day and National Day holidays.
从大学二年级开始,我就在暑期和“五一”,国庆期间为两家旅游公司兼职作导游

A student in the freshman or Sophomore class at a secondary school or college.
中学或大学的一、二年级学生

When my son was a high-school Sophomore, he got a part-time job-- sacking groceries at a supermarket. He came home all smiles.
我儿子在一所中学读二年级时，在一家超级市场找到了一份包装商品的业余工作。他满面笑容地回到了家。

When I was a Sophomore, I took part in the training class of computer operation and got a certificate.
上大二时．我参加了计算机操作培训班的学习并获得证书。

It states that this year the school's improvements in its API scores were aided by two "good cohorts": the Sophomore and senior classes
今年学校的学术水平统计成绩有了提高，主要是因为二年级和四年级的学生表现很好。

When I came home for the holidays my Sophomore' year of college, I thought I knew everything. I was on this big female independence kick.
“记得在我大学二年级那年回家度假的时候，我自认为已经无所不知了，尤其是对于男女的不平等的现象可谓是深恶痛绝。