Definition
without success; having no result.
徒勞地；無效地；枉然地
Despite his best efforts, his attempt to fix the old computer was in vain.
儘管他盡了最大努力，但他修理舊電腦的嘗試還是徒勞無功。
They tried to convince her to change her mind, but it was all in vain.
他們試圖說服她改變主意，但一切都是徒勞。
After hours of searching, they found their efforts to find the missing keys were in vain.
經過幾個小時的搜索，他們發現尋找丟失鑰匙的努力是徒勞的。