酒店员工在任何时候都必须礼貌地对待客人。

Hotel staff must at all times treat guests with ___courtesy.

他至少应该有点礼貌，说声对不起。

He could at least have had the ___courtesy to say sorry.

企业应努力提升一线员工的礼貌素养。

Businesses should strive to improve the ___courtesy of their frontline staff.