短語 a bolt from the blue, 意思是發生了完全意想不到的事情，晴天霹靂。
The prime minister's resignation was a bolt from the blue.
It was a real bolt from the blue when I bumped into my first ever boyfriend in the supermarket.
The announcement about redundancies was a bolt from the blue for the workers in the office.
另一個短語 out of blue 含義相似 ，也有突如其來，意想不到的意思。
His marriage proposal came out of the blue – but she said yes!