占线音

例句：

1. 1. The phone is currently in a busy line.
   电话现在正忙。
2. 2. If you need to call me, I'll be in a busy line.
   如果你需要打电话给我，我会在忙线中。
3. 3. The line was busy because of the heavy traffic.
   因为交通拥堵，线路很繁忙。