核心句型：
I'm so sorry to keep you cooling your heels.
非常抱歉讓您久等了。
cool one's heels字面理解意思是：“冷卻某人的腳后跟”。這里的heel一開始不是指人的腳后跟，而是指馬蹄。在火車、汽車發明之前，馬匹是人類最主要的交通工具，在長途旅行中，經過長時間跋涉，馬蹄就會過度發熱，騎馬的人不得不中斷旅行讓馬休息一下。現在，這個詞已經轉義為：“苦苦等候，坐冷板凳”了。因此，當美國人說"I'm so sorry to keep you cooling your heels."時，他/她要表達的意思就是:"I'm so sorry to keep you waiting for so long."、"I'm sorry to have you kicking your heels for so long."。
情景對白：
Benjamin: I'm so sorry to keep you cooling your heels. Have a seat.
本杰明：很抱歉讓你久等了，請坐。
Client: I hope you were expecting me. Here are the details about our cooperation. Please have a look at it.
客戶：我想你之前也等著我來吧。這是我們合作的詳細資料，請看一下。
搭配句積累：
①I was on emergency temporarily and couldn't get away immediately.
我臨時有事，一下子走不開。
②Let's begin right now.
我們馬上開始吧。
③We were caught in traffic jam.
我們堵車了。
④We will serve you as quickly as possible.
我們會盡快為您服務。
單詞：
1. temporarily adv. 臨時地
His job here is only temporary...
他在這兒的工作只是臨時的。
Most adolescent problems are temporary.
多數青少年問題是暫時性的。
The peace agreement has at least temporarily halted the civil war...
該和平協定至少暫時停止了內戰。
2. traffic jam 交通堵塞
The concurrent political rallies caused a traffic jam.
同時舉行的政治集會引起了交通堵塞。
His car was stalled in a traffic jam.
他的車子在交通阻塞中動彈不得。
He was late because he was caught in the traffic jam.
他遲到了，因為遇上了交通阻塞。