员工必须始终礼貌对待顾客。

Staff must always treat customers with ___courtesy.

他甚至没有最起码的礼貌来回复我的邮件。

He didn't even have the ___courtesy to reply to my email.

事业上的成功常常取决于表现出基本的礼貌。

Professional success often depends on showing basic ___courtesy.