形容詞 vain:

1. characteristic of false pride; having an exaggerated sense of self-importance
   同義詞：conceited, egotistic, egotistical, self-conceited, swollen, swollen-headed
2. unproductive of success
   同義詞：bootless, fruitless, futile, sleeveless

1. They endeavoured to make her happy but in vain.
   他們盡量使她快樂，卻徒勞無功。
2. She is vain of her voice.
   她自以為她的聲音了不起。
3. He tried in vain to catch the butterfly on the flower.
   他白費力氣想抓住停在花上的蝴蝶。
4. All his father's exhortations were in vain.
   他父親的一切勸告都無效。
5. She is vain and foolish, and yet people like her.
   她自負而愚蠢，然而人們喜歡她。
6. A vain person; a dandy.
   虛榮的人; 愛炫耀的人
7. All our work was in vain.
   我們的工作全都白干了。
8. We tried in vain to make him change his mind.
   我們想使他改變主意，結果是白費心機。