bark at the moon 空喊；徒劳地吵闹

“向着月亮嚎叫”，引申为“空喊；徒劳地吵闹”。类似的表达还有bay at the moon，意为“费力做没有价值的事，徒劳”。

而月亮对此也有回应：

The moon does not heed the barking of dogs. (=Does the moon care for the barking of a dog?）

即“月亮不理狗的狂吠”，引申为“对无稽责难置之不理”。

例句：

Those who protested against the president’s decision were actually barking at the moon, since they were in a powerless minority.

由于他们属于软弱无力的少数，他们反对总统的决定实际上是枉费唇舌。