in vain​ 中文含义：徒劳地，白费力气 通俗理解：付出了努力却没有得到任何结果，就像竹篮打水一场空。 例句： They searched for the missing keys in vain, and had to call a locksmith.​ （他们白费力气寻找丢失的钥匙，最后不得不叫锁匠。） All his attempts to persuade her were in vain — she refused to change her mind.​ （他所有的劝说都是徒劳，她拒绝改变主意。）