请不要挂断电话；您的来电正在等待接通。

Please don't hang up; your call is ___on ___hold.

我被搁置在线上等待了二十分钟，才得以和一位代表通话。

I was left ___on ___hold for twenty minutes before I could speak to a representative.

客服线路正忙；您很可能会被要求在线等候。

The customer service line is busy; you'll likely be put ___on ___hold.