She can be a real pain when she's in a bad mood.

她脾气不好时，真是令人头痛。

She is in a bit of a bad mood because she's just given up smoking.

因为刚戒烟，她心情有点糟。

It is widely accepted that having not enough sleep can leave people in a bad mood.

人们普遍认为睡眠不足会让人心情不好。

The incident put her in a bad mood.

这件事弄得她心情很不好。

It put me in a bad mood for the rest of the day.

那事让我整天再也没了好心情。