笛声

We heard the whistle of a train.

们到火车的汽笛声。

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。

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

些汽车到愈愈的警笛声便停下。

I heard police sirens in the distance .

到警笛声从远处传。

In big cities you always hear sirens all the time.

在大城市里, 你总能到警笛声。