teach a pig to play on a flute

• v. 做不可能做到的事

teach a pig to play on a flute的用法和样例：

例句

用作动词 (v.)

1. I don't expect him to do impossibilities.
   我并不指望他去做不可能做到的事。
2. A wise man never attempts impossibilities.
   聪明人绝不做不可能的事情。