fifth wheel ------ 多余的人
英文释义
A person who serves no function.
例句
When my father gave all my responsiblies in our family's business to my brothers, I felt like a fifth wheel, and so I started looking for another job.
当我父亲把家里的生意都交给我的哥哥们时，我觉得自己是个多余的人，所以开始找别的工作。