I already know all this! Now, you're just preaching to the choir.

这些我都知道！现在，你只是在" 白费口" 。

Still Matthew said nothing and Marilla had a sense of having wasted words and breath.

马修仍然一言不发，玛丽拉有种白费口的感觉。

The official in the jail wasted his words to induce Samuel.

监狱里一官员白费口来劝诱塞缪尔。

Save your breath, Gaby. It's not gonna happen.

别白费口 布 不可能的。

Save your breath. She’s already made up her mind.

【breath】别白费口，她主意已定。

Her good advice was wasted on the children.

【waste】她对孩子们的规劝是白费口。

Don’t try to reason with Paul – you’re wasting your breath.

【waste】别跟保罗讲道理，你在白费口。

Sometimes a person fights a battle that has been decided or keeps arguing a question that has been settled. We say this is like " beating a dead horse."

有时，一个人可能一直就已经决定的战争而战斗，或者一直争论已经解决的问题。我们说，这简直是白费口(就好象beating a dead horse)。