I have to work overtime. 我要加班。
overtime 加班；夜班

例句：
 

I haven't finished work today,I have to work overtime.
我还没有完成今天的工作，我要加班。

I don't want to work overtime every night,I'm fed up with it.
我不想每晚加班，我受够了。

A:Would you like to have dinner with me tonight?
今晚和我吃晚饭怎么样？
B:I'd love to,but I have to work overtime.
我也想，但是我要加班。

背景音乐：
Bobby Tinsley-Missing youMa