我知道她生我的气，但我并不为此担心。

I know she's angry with me, but I'm not ___losing ___sleep ___over it.

我太忙了，没时间为此担心。

I was too busy to ___lose ___sleep ___over it.

不要为考试结果担心；你已经尽力了。

Don't ___lose ___sleep ___over the exam results; you did your best.