这个现象与当火车向远处后退时的汽笛响声类似。

It is similar to how the sound of a train's whistle seems to shift as it recedes into the distance.

youdao

这个现象与当火车向远处后退时的汽笛响声类似。

It is similar to how the sound of a train's whistle seems to shift as it recedes into the distance.

youdao