《太平广记·卷七十·女仙十五》
到了第二天，他又慌忙起来，取笔把墙上诗的第二句改为 天风飞下步虚声 。
及明日，又惊起，取笔改其第二句曰 天风飞下步虚声 。
The next day, he got up again in a panic and took a pen to change the second sentence of the poem on the wall to: The wind from heaven flies down and steps on the empty sound.