Once you stop using your brain you soon go stale.

一旦你停止动脑筋,你很快就会变迟钝。

《柯林斯英汉双解大词典》

Once you stop needing, that is when you can find love.

一旦你听只需要，你就能够发现爱了。

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Once you stop using it, your lashes, will eventually go back to their natural state.

一旦你停止使用，你的睫毛就会回复到自然状态。

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Archivist Constance Potter says genealogy can be addictive: once you start, it is hard to stop.

VOA: special.2010.06.28

And, in fact, once you teach an animal something, if you stop doing the teaching the response goes away and this is known as extinction.

事实上，条件反射形成以后，如果得不到强化,条件反应就会逐渐消失,这就是消退。

耶鲁公开课 - 心理学导论课程节选

But another possibility is once you do something it's kind of hard to stop.

但也有可能是因为,婴儿很难使自己的惯性动作停下来

耶鲁公开课 - 心理学导论课程节选

"Once you stop the actual brushing, the enzyme will still be working, " he says.

CNN: Pet grooming tools for a less hairy summer

Once you stop to think about it, the solution is obvious.

FORBES: Workforce Diversity -- Walgreens and the Obvious Solution

One of the side effects, which nobody actually likes to talk about, for all of these medications, is that once you stop taking them people start gaining weight again.

NPR: Slate's Medical Examiner: Xenical OTC