课外时间的英语（每日英语whenpigs）

课外时间的英语（每日英语whenpigs）He plans to clean his house every week but he will probably do it only when pigs fly.

when pigs fly/pigs might fly/flying pig 猪是绝对不可能会飞的，所以这个俚语引申出“绝不可能”的意思。

-At a point in time that will never come to pass.

I'm sure that David would be happy to pay for everyone—when pigs fly that is.

Her crazy mother said that being so lazy Megan is going to be rich one day for sure and without any hard working job. Come on when pigs fly!

He plans to clean his house every week but he will probably do it only when pigs fly.