They tried to rally the pound sterling but in vain.(他們企圖恢復(fù)英鎊幣值，但勞而無功。)

They tried in vain to persuade her to go.(他們極力勸說她去，但枉費(fèi)了一番口舌。)

I try to sing a song, but in vain.(我想唱一支歌，但是唱不出來。)

Time can prove my efforts will not end in vain.(我相信時間會證明我的努力不會白費(fèi)。)

They sought in vain for somewhere to shelter.(他們怎么也找不到一個藏身的地方。)

He try to deceive his mother but in vain.(他試著欺騙他的媽媽，但失敗了。)

They may cry in vain.(他們的呼吁可能是徒勞的。)

He tried to cover up his mistakes but in vain.(他試圖掩飾他的錯誤，但辦不到。)

But he and others have not done so in vain.(不過他和其他人的行動不是徒勞的。)

I know it is in vain to dispute with you.(但我心知肚明，任何爭辯都是徒勞。)