A third wheel/ a fifth wheel 多余；电灯泡

third 第三个

fifth 第五个

wheel 车轮

I don’t think I’ll join you this time. Whenever I go out with you guys, I just feel like a third wheel.我这次就不跟你一块了，每次跟你们一块出去，我都感觉我像个电灯泡。

I just wanted to feel like part of the team instead of a fifth wheel.我只是想让自己感觉是这个团队的一员，而不是多余的。

I didn't realize that the party was for couples only, so when I showed up alone, I felt like a fifth wheel.我不知道这个聚会是只针对情侣的，所以当我一个人出现在那的时候，我感觉自己很多余。