People usually draw the curtains once it gets dark.

天一黑，人们通常就会拉上窗帘。

《柯林斯英汉双解大词典》

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

Well, I didn't neither, but all at once it popped onto me that it was Friday.

嗯，我也是，但我突然想到今天是星期五。

youdao

But once it was built, family members of the dead, Vietnam veterans, and the general public accepted its beauty and strong emotion.

VOA: special.2009.05.06

If you make Jell-o and you make it right, then once it's set or gelled, it has mechanical properties.

如果你用正确方法做出了吉露果冻,它一旦凉下来定了型,就有了机械性能

耶鲁公开课 - 生物医学工程探索课程节选

And once you know how it sounds, making those sounds for yourself would be a lot easier to do.

一旦你知道该怎么发音，你就能更加容易地把它说出来。

想征服英语的话 - SpeakingMax英语口语达人

Surveillance technology, once it is installed for public safety purposes, quickly infiltrates other parts of our lives.

FORBES: Spotting Evil

For once it seems like the administration and the internet activists are on the same page.

FORBES: Why An Internet Blackout For SOPA And Not CISPA?

Once it was part of the Mid-Wilshire District and home to the city's movers and shakers.

NPR: $150 Million Reboot For Hollywood Temple To Stars