Once you've broken the seal of a bottle there's no way you can put it back together again.

一旦你撕开瓶子的封口,就没法将它重新合上。

《柯林斯英汉双解大词典》

You know the theory that earth's continents were once joined together and only split apart relatively recently?

大家都知道地球上的大陆曾经连在一起，直到最近才分开的那个理论吗？

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His uncle Tommy once took on three men together in a brawl.

他的叔叔汤米有一次和三个人打架。

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Once a month, people come together at a restaurant in Washington to listen to several storytellers perform.

VOA: special.2009.03.27

You have to touch each of the 16 elements once as I go across the blackboard to actually merge them together, alright.

为了将这16个元素,合并到一起,对每个元素都只会用到一次。

哈佛公开课 - 计算机科学课程节选

and then once we turn in the completed paper that we worked on together,

在上交我们一起合作完成的报告后，

在模拟审判课堂 - SpeakingMax英语口语达人

One whispered rumor can obscure the truth and set off violence between communities that once lived together in peace.

WHITEHOUSE: Indonesia��s Example to the World

The coalition was once bound together by affinity, with the two parties discovering they agreed on a good deal, including school reform, localism and paying off the deficit.

ECONOMIST: Britain��s feuding coalition government

Thus the narrator only suffers the full effects of his beloved grandmother's death when he later stays at the same hotel at Balbec, where they had once stayed together.

ECONOMIST: Proust in translation