Secondary labor market jobs provide fewer benefits and include lower-skilled jobs and lower-level service sector jobs.
二级劳动力市场工作提供的福利较少，包括低技能工作和低级别服务部门工作。
社会学 Crash Course
There’s the primary labor market and the secondary labor market.
有初级劳动力市场和次级劳动力市场。
英语百科
Secondary labor market
The secondary labor market is the labor market consisting of high-turnover, low-pay, and usually part-time or temporary work. Sometimes, secondary jobs are performed by high school or college students. The majority of service sector, light manufacturing, and retail jobs are considered secondary labor.