笛声

We heard the whistle of a train.

我们了火车的汽笛。

I heard police sirens in the distance .

我笛从远处传来。

In big cities you always hear sirens all the time.

在大城市里, 你总能笛。

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

这些汽车来近的笛便停了下来。

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

当中午的笛响起时，工厂里的嘈时停止了。