Parents campaigned in vain for her reinstatement.

家长们为她的复职而奔波，但是毫无结果。

《柯林斯英汉双解大词典》

It was a vain attempt to shift the responsibility for the murder to somebody else.

把这项谋杀的罪责转嫁于他人是徒劳之举。

《柯林斯英汉双解大词典》

She searched in vain for her passport.

她翻找自己的护照，但没找着。

《牛津词典》

America's true unemployment rate may, in fact,be higher than the number provided by the Labor Department, which does not include people who searched for work in vain and have given up, or those who settled for part-time work.

VOA: standard.2009.07.02

"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

Reviews are for the vain, you might say.

FORBES: Google Play User Reviews Have Low Marks For Facebook Home

With 17 minutes remaining, Graham crossed for McArthur to head over as Accies searched in vain for a leveller.

BBC: Hearts striker Christian Nade

Walking through the halls for two hours was like marching through a desert, searching in vain for a flowing spring of argument or works that would enliven my sense of the period.

WSJ: Light Years: Conceptual Art and the Photograph, 1964-1977 | Snapshot of a Movement | By Richard B. Woodward