我昨天买了一个扩音机扩音机。

I just bought an amplifier yesterday.

目前，扩音机我们正好缺货，不过随时可能有货供应。

We haven't any amplifiers in stock just at present; but they should come in any moment.

系在一棵树上的扩音机里传过来人家的演讲，她看见蓓蒂要听就不说话了。

She gave up talking as she saw bette was trying to listen to the speech that was being relayed through a loud-speaker tied to one of the trees.