直到太阳落山他们才停止工作。

Not until the sun had set did they stop working.

youdao

他直到太阳落山以后才回来。

He did n't come back until the sun had set...

youdao

现在我并不会因为太阳落山而停止工作(实际上我就没注意到现在是白天还是晚上)我经常持续工作，直到我觉得真的需要休息一下为止。

Instead of stopping work because the sun just happened to go down (I often lose track of whether it's day or night), I tend to keep working until I feel I really must take a break.

youdao