Third wheel，in english ：One who deters the socialization of a couple, perhaps when being invited out of pitty or through a feeling of duty. The third wheel may feel uncomfortable about watching the couple canoodle on his her her sofa,

Third wheel呢，是这样的一个人，他妨碍到了一对夫妇或者男女朋友的交往，经常呢，他是出于同情或者责任而被邀请。电灯泡看到别人一对在一起亲热，经常会感到不舒服；

举例：

1. Well, if your bring your girlfriend, I'll have to take my cousin with me, cause I don't wanna be the third wheel.

不行，如果你带了你的女朋友，那么我就要带我的表妹，因为我可不想当电灯泡。

2. I'm not going to the movies with you guys tonight, I don't want to be a third wheel. It is like watching a poorly scripted romance movie!

今晚我不和你们去看电影了，我才不要做电灯泡。我看你们在一起就好比在看一场很糟的爱情电影。