Sunday is the only day when I can relax.

星期日是我唯一可以休息的日子。

《牛津词典》

He's going to fix a time when I can see him.

他将确定一个我可以见他的时间。

《柯林斯英汉双解大词典》

I don't know exactly when I can come.

我不知道具体什么时间我能来。

youdao

There was nothing I could do. When you have this kind of a problem, you can only take care of your body.

VOA: special.2010.08.09

I don't hear most of it. But there are moments, and they're moments that give me pleasure when I can say, "Oh,yeah. That's what he's doing there."

我也只能听出一小部分，但是有时候，这些时候总是让我激动，我会发现，哦对，这正是作曲家在做的“

耶鲁公开课 - 聆听音乐课程节选

so at the moment when I can't go back to see her, I go to training academies.

所以我不能回去找她的时候，我就去培训学校。

做头发是免费的 - SpeakingMax英语口语达人

In the hope of not losing my game altogether, I play when I can.

NEWYORKER: Personal Best

Are they going to forgive me when I can't react and listen to them?

CNN: Seizures: When 'electrical brainstorm' hits

Why remake A Nightmare on Elm Street when I can just watch the original?

FORBES: Lies, Damned Lies and Piracy