A bank of clouds had built up along the western horizon.

一堆堆的云沿着西边的地平线积聚起来了。

《柯林斯英汉双解大词典》

Mother says he made 'em that color with always lookin' up at th' birds an' th' clouds.

妈妈说，因为他总是抬头望着鸟和云，所以他才把它们变成那种颜色。

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In sharp contrast to her mood, the clouds were breaking up to reveal a blue sky.

乌云渐渐散开，露出了蓝天，这和她的情绪形成了鲜明的对照。

《牛津词典》

But things are beginning to look up. Carefully,cautiously, we can say that there is a break in the clouds,".

VOA: standard.2009.04.26

And off in the violet distance behind them, prodding them along in their efforts, are the faint outlines of silvery cumulus clouds boiling up in the haze.

BBC: Before the storm in Cameroon

The crown was lighted in a way "to create the vision of the moment after the clouds open up and the rain comes through, " said Mr. McKenzie.

WSJ: Promoting 'The Bible' With Crown of Thorn

Clouds had started to build up, and clouds always mean big bumps.

FORBES: Bleary-Eyed In Bozeman