The number you are calling is busy right now. Please call later.或

The number you are calling is out of service.

电信局好像会这样说。

如对方有信箱的话，语音有时也会说 'the person you are calling is not available (or 'on the other line'). if you would like to leave a voice mail, please press pound (#; or star *).

占线的话不会有语音提示的，你会听到忙音。

The line is busy.