workhorse

中文： 役马、重负荷机器、挑大梁的人

1. A horse used primarily for manual labor: a draft horse (draught horse). · Near-synonym: carthorse
2. A person or piece of equipment that performs a lot of work, especially one heavily relied upon to perform consistently and regularly. (figuratively) · Those old machines are not very glamorous, but even 20 years after their introduction, they are still the workhorses of the industry.

复数 workhorses