During the hours spent waiting in vain to see a bone doctor, I decided to take another track and try acupuncture.

在白白等待看骨科医生的几个小时里，我决定换一种方式，去尝试针灸。

youdao

He stopped at the door, waiting in vain for her to acknowledge his presence.

他停在门口，徒然地等着她跟自己打招呼。

《柯林斯英汉双解大词典》

Sadly, they may be waiting in vain.

说来遗憾，他们可能发现自己的等待是徒劳的。

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called Northern Lights, who perform the Bob Marley classic, "Waiting In Vain."

VOA: standard.2010.07.22

Those hoping for a big American diplomatic effort may be waiting in vain.

ECONOMIST: American diplomacy

All he did was work in the souks, the old markets of Aleppo, waiting in vain for the tourists to come back.

CNN: In Syria, searching for loved one taken away

With the Enyimba defence waiting in vain for the offside flag, Zitouni found himself unmarked in the six-yard area but headed over the bar from close range.

BBC: SPORT | Football | African | Esperance hold Enyimba