adj. 徒劳的；自负的；无结果的；无用的
用作形容词(adj.)
用作定语
～+ n.
She is one of those vain people who never take others' advice.
她属于那种自负得从不听别人劝告的人。
I don't like a vain woman.
我讨厌爱慕虚荣的女人。
He made a vain attempt to reach the drowning child.
他试图接近那个快淹死的小孩,但没有成功。
用作表语
S+be+～
All my efforts were vain.
我的一切努力都白费了。
S+be+～+ prep .-phrase
He's very vain of his abilities.
他对于自己的能力很自负。
It is/was+～+to- v
It is vain to resist.
抵抗是没用的。
用作宾语补足语
S+V+O+～
Too much praise can make a man vain.
过度的赞扬会使人自负。
1. He is still vain enough to dye his hair red.
他还是很虚荣，把头发染成了红褐色。
2. It became obvious that all her complaints were in vain.
很明显她所有的抱怨都是白费口舌。
3. I am not a vain creature.
我不是个爱慕虚荣的人。
4. She is perceived as vain, spoilt and promiscuous.
她被认为是个被人惯坏了的、既虚荣又淫乱的女人。
5. He was self-important, vain and ignorant.
他傲慢自负，虚荣无知。
6. Parents campaigned in vain for her reinstatement.
父母们呼吁给她复职，但结果却只是徒劳。