If you happen to make it to the goal, it will have been by luck or chance and is not repeatable.

如果你碰巧实现了一个目标，你可以靠运气或者机会，但是运气或机会是没有重复性的。

youdao

Optimists also figure that bad things happen occasionally, and by chance, not because of one's own mistakes; and they believe those bad things are unlikely to happen again.

乐观主义者也认为坏事只是偶尔意外出现，不是因为人做错了；而且他们相信坏事不可能再次发生。

youdao

No, it's not just that some happen to be rich and others by chance are poor.

不，某些人碰巧富有而另一些人偶然贫穷，这是毫无根据的。

youdao

He was that odd breed, a reverential rebel, and he was guided by a faith, which he wore lightly and with a twinkle in his eye, in a God who would not play dice by allowing things to happen by chance.

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"The stark reality behind the statistics and one of the hardest things for victims' families to deal with is that drink driving does not happen by chance, " he said.

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Also, should this by a freak of chance not happen, how long would it have taken for the twins to sell it?

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