Please don't make silly jokes during the client presentation; they are very formal people.

客戶簡報時請別開無聊的玩笑，他們是很正式的人。

The manager warned new hires that silly mistakes on invoices can cost the company money.

經理提醒新進員工，發票上的愚蠢錯誤可能讓公司賠錢。

It felt silly to argue with the hotel clerk over such a small booking error.

為了這麼小的訂房錯誤跟飯店櫃檯人員爭執，感覺很傻。