一旦发现他本可以得到这个工作，他会感到懊恼的。

He'll kick himself when he finds out he could have had the job.

《牛津词典》

一旦发现任何危险，雄性就用鼻子轻拍地面。

As soon as he detects any danger, the bull taps on the ground with his trunk.

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一旦发现危险的迹象，鱼群就会尽可能地游近彼此。

At the first sign of trouble, schooling fish swim as close together as they can get.

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Turns out that once you get past the hormonal blast of adolescence about 10% of dreams have explicit sexual content.

研究还发现一旦你过了,荷尔蒙旺盛的青春期,你有10%的梦都是和性有关的。

耶鲁公开课 - 心理学导论课程节选

And once you start to see this, we realize, of course, our life is filled with this aspect.

一旦明白了这一点,我们就会发现,生活中处处都是这种体验

耶鲁公开课 - 死亡课程节选

What starts out looking very benign, once you look closer, is pretty fierce and filled with violence, and that's why people want to leave.

乍一看非常良善，一旦仔细看，会发现它粗暴且充满暴力，而这就是人们想脱离的原因。

耶鲁公开课 - 公正课程节选