Rules and regulations, once set up, should not be turned into a dead letter.

规章制度一经订立，不应成为一纸虚文。

《新英汉大辞典》

Once set, this parameter cannot be changed or reset.

一旦设置好了，该参数就无法进行修改或重新设置。

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Many states once set their minimum drinking-age at 18.

许多州曾把最低饮酒年龄设在18岁。

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His right arm was crushed. Once set,he would never be able to bend his arm again.

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He believed whatever one wag once set of monks, "I sleep, I eat, I digest," and they prayed, of course.

他对修士们的态度就像某个僧侣说的,"吃了就睡,睡了再吃",当然他们也会祈祷

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So it's a really powerful and simple formalism, once we set up what is needed the go through it, right?

因此这是一种很强大而简单的形式,一旦我们定下需要什么,就可以推导出它，对吧？

麻省理工公开课 - 热力学与动力学课程节选

The law, once set in motion, can be like a huge ship propelled by logic and precedent.

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Another example: Brokerage commissions for buying and selling stocks were once set by the SEC at a fixed level.

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For Jimmy, the advantage of his system is that once set up, it can be largely left to run itself.

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