All our efforts were in vain.

我们的所有努力都付诸东流了。

《牛津词典》

She searched in vain for her passport.

她翻找自己的护照，但没找着。

《牛津词典》

They tried in vain to persuade her to go.

他们极力劝说她去，但枉费了一番口舌。

《牛津词典》

It is rather for us,the living, we here be dedicated to the great task remaining before us - that,from these honored dead we take increased devotion to that cause for which they here, gave the last full measure of devotion - that we here highly resolve these dead shall not have died in vain;

VOA: special.2011.02.07

"For we assert," he says, "nature does nothing in vain and man alone " among the animals has speech.

他说，“因为我们主张自然演变并不无道理,而人类独立于其它动物之外,是因为我们有辩论能力。

耶鲁公开课 - 政治哲学导论课程节选

Specifically you'll see that the rationale for observing the Sabbath is different. God's name in Deuteronomy 5 is not to be used in a vain oath as opposed to a false oath. There are differences in the meaning.

你会发现两者对守安息日习俗的论述是特别不同的,《申命记》第五章的描述是，不可以妄称上帝的名,而不是不可以以上帝的名义作假誓，它们表达的意思。

耶鲁公开课 - 旧约导论课程节选

In vain has it touted the completed or continuing trials of 111 other defendants.

ECONOMIST: The Hague war-crimes tribunal

Some of these were contained electronically so much of the shredding was in vain.

FORBES: Rajaratnam Evidence -- Where Are The Emails?

My kids usually pitch in, flipping over sofa cushions, rummaging through their toy box in vain.

WSJ: Track Your Lost iPhone and Other Gear With These Gizmos