the third wheel

基本解释

"I felt like the third wheel, " she said.
"我觉得自己像个电灯泡，"她说。
Tonny: No, I don't want to be the third wheel.
哦，不要了，我可不想当电灯泡哦。
But when you just want pure speed its stands upright with the third wheel on top, which supposedly helps keep it balanced.
你要是纯粹想体验速度，它可以竖起来，第三只轮子置于顶部，保持车体平衡。

In the publicity surrounding the new Twilight film, Eclipse, actor Taylor Lautner often looks like the third wheel.
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With John Krasinski, as the eternal third wheel and second fiddle.
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The third view-busting project is the Millennium Ferris Wheel on the south bank of the Thames, but since this would be only temporary—five years has been suggested—it is causing less worry.
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