他的笑声中透着一丝空虚，仿佛只是为了掩饰内心的空洞。

There was a ___hollowness in his laughter, as if it was just to cover up the emptiness inside.

尽管事业成功，她内心仍感到一种空虚感。

Despite her career success, she felt a deep ___hollowness inside.

钟声的空灵回响在山谷中回荡。

The ___hollowness of the bell's sound echoed through the valley.