third wheel 电灯泡

俗话说，“三人行，必有一个电灯泡”。你有过当“电灯泡”的经历吗？“电灯泡”，本意指白炽灯（bulb），现在也常比喻“男女谈恋爱时碍手碍脚又不知趣的第三人”，与英文流行语“third wheel”意思相近，表示“an unwelcome or extra person”，就像多余的轮胎一样。

例句：

当凯利邀请我去看电影时，我不知道她的男朋友会和我们一起去。整个晚上我都觉得自己像个电灯泡。

When Kelly invited me to go to the movies, I didn't know that her boyfriend would be joining us. I felt like a third wheel the entire night.

我很想和你们一块儿出去，可我不想当电灯泡。

I'd love to go out with you, but I hate to be a third wheel.