work extra hard

工作特别努力

I paid extra for a good room.

为了住个好房间，我额外付费了。

The service charge is an extra.

服务费另计。

do extra work

加班

Festival food will be served without extra charge.

节日食物供应不额外收费。

In our hotel room service is not extra.

我们旅馆不另收房间服务费。