笛声

We heard the whistle of a train.

我们听了火车的汽。

The din in the factory ends abruptly when the noon whistle sounds.

当中午的响起时，工厂里的嘈杂顿时停止了。

The cars had stopped at the sound of the approaching siren.

这些汽车听的便停了下。

I heard police sirens in the distance .

我听从远处传。

In big cities you always hear sirens all the time.

在大城市里, 你总能听。