vain

The rescue team made a vain attempt to reach the climbers during the blizzard.

(Chinese) 救援队在暴风雪中试图营救登山者，但徒劳无功。

All their efforts were in vain as the contract was eventually awarded to a competitor.

(Chinese) 他们所有的努力都白费了，因为合同最终判给了竞争对手。

The vain actor spent hours in front of the mirror before every public appearance.

(Chinese) 那位虚荣的演员在每次公开露面之前都要在镜子前待上几个小时。

She was too vain to admit that she had made a simple mistake in the calculation.

(Chinese) 她太虚荣了，不愿承认自己在计算中犯了一个简单的错误。