白费力气

• lash the waves
• mockery
• lick a file
• gnaw a file
• plough the air

例句

1. 大夏天推销大衣真是白费力气。
   Trying to sell overcoats in midsummer is a real mug's game.
2. 他白费力气想抓住停在花上的蝴蝶。
   He tried in vain to catch the butterfly on the flower.
3. 过去的事哭也是白费力气。
   It is no use crying about the past.
4. 在无人岛上夸耀富有也是白费力气。
   It is of no use boasting of being rich on a desert island.

近反义词

【近义词】

• 空费
• 空耗
• 枉费心机