笛声

We heard the whistle of a train.

我们听到了火车的汽笛声。

I heard police sirens in the distance .

我听到警笛声从远处传来。

In big cities you always hear sirens all the time.

在大城市里, 你总能听到警笛声。

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

这些汽车听到来近的警笛声便停了下来。

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

当中午的笛声响起时，工厂里的嘈杂声顿时停止了。