We heard the whistle of a train.

我们听了火车的汽声。

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

当中午的声响起，工厂里的嘈杂声止了。

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

这些汽车听愈来愈的声便了下来。

I heard police sirens in the distance .

我听声从远处传来。

In big cities you always hear sirens all the time.

在大城市里, 你总能听声。