It is known as the music room because once it was used for music lessons.

它被称为音乐室，因为它曾用来上音乐课。

youdao

Wuxi is famous for its water but it once had trouble because of water.

无锡因水著名，也曾因水而困。

youdao

He used to return home at least once a year, but hasn't been back for almost three years now because of the hard job in a crayon factory.

他过去每年至少回家一次，但由于在蜡笔厂工作太辛苦，他已经快三年没回家了。

youdao

They had to be home, and they had to stick to their plans, because you had no way of communicating with someone once you left for your destination.

VOA: special.2009.09.14

And, so, people would come down and they'd have their pictures taken with a picture, as if it was part of the true cross of the crashed Vendome column; because for once they had won, for once they had won.

所以,人们会来这里,和那张画合影留念,仿佛这是,旺道姆广场的纪念柱的墓碑,因为他们曾经胜利过,他们曾经胜利过

耶鲁公开课 - 1871年后的法国课程节选

That's why your operating systems and your personal computers often crash for no apparent reason. Just because two things happen to, once in a while, occur at the same time.

这就是为什么你的电脑或者操作系统,经常会毫无预兆的崩溃了,这是因为两件事情正好同时发生了，通常还有人工输入。

麻省理工公开课 - 计算机科学及编程导论课程节选

They are in high spirits because for once in a way they have enough to eat.

NPR: Excerpt: 'All Art Is Propaganda'

It was great for the special school kids because for once they were the best at something, whizzing around in their wheelchairs.

BBC: NEWS | UK | Going for gold the Duke's way

At BMO, where investors heaved a sigh of relief because for once there were no large, unexpected charges, investment banking earnings slumped 7.5%, while profit from retail operations was essentially flat.

FORBES