put a damper on something 潑冷水

說明：

damp 指潮濕，是形容詞。damper 則指使人掃興的人或事，是名詞。有關介系詞 on 的用法，請參照 sleep on something 條目。

例子：

I don't want to put a damper on your plan, John. But you have to be more realistic.

by Thomas Shum