"pigs might fly" in Chinese (Simplified)
太阳从西边出来（比喻不可能）等母猪会飞
Definition
这个表达用来说明某事极不可能发生，基本不会发生。
Usage Notes (Chinese (Simplified))
非正式、带有幽默或嘲讽意味。通常用于回应该提议或承诺不现实。常见类似表达有“太阳从西边出来”。
Examples
Do you think he'll finish his homework on time? Pigs might fly.
你觉得他会按时完成作业吗？**太阳从西边出来**。
She thinks she can be a movie star? Well, pigs might fly.
她觉得自己能成为电影明星？**等母猪会飞**吧。
Will Dad buy me a new phone? Pigs might fly!
爸爸会给我买新手机吗？**太阳从西边出来**！
If you think Jenny will apologize, pigs might fly.
你觉得珍妮会道歉？**等母猪会飞**吧。
He promised to stop being late. Yeah, and pigs might fly!
他说过要不再迟到。是啊，**等母猪会飞**！
Maybe I'll win the lottery tomorrow...but pigs might fly.
也许我明天中彩票……不过**太阳从西边出来**。