警报器一响，就是要所有人离开大楼。

The siren was a signal for everyone to leave the building.

《牛津词典》

如果我们中有人离开了公司，应该怎样？

What happens if one of us leaves the company?

youdao

你听我说，没有人离开这个国家。

Listen, nobody is leaving this country.

youdao

It's an act of free will. Somebody's leaving.

这是自由意志的选择，有人会离开。

麻省理工公开课 - 固态化学导论课程节选

because someone turned the gas off and turned it back on and then left.

因为有人把瓦斯关了以后，又打开，忘记关上就离开了。

Make sure 课堂 - SpeakingMax英语口语达人

When he is gone from Moscow and then St. Petersburg, there was always this tendency to have these sort of cabales to get together and sort of plot.

当他离开莫斯科和圣彼得堡外出时,就会有人秘密集会,结党营私,秘谋造反

耶鲁公开课 - 欧洲文明课程节选