如果没有事实支持，再漂亮的承诺也是空洞的。

Rúguǒ méiyǒu shìshí zhīchí, zài piàoliang de chéngnuò yě shì kōngdòng de.

Without facts to support it, even the most beautiful promise is empty.

这些口号听起来很好听，但有点空洞。

Zhèxiē kǒuhào tīngqǐlái hěn hǎotīng, dàn yǒudiǎnr kōngdòng.

These slogans sound nice, but they are a bit empty.

他总是说一些空洞的道理，却不给出具体的办法。

Tā zǒngshì shuō yìxiē kōngdòng de dàolǐ, què bù gěi chū jùtǐ de bànfǎ.

He always talks about empty principles but never offers concrete methods.