out of the blue

adv.出乎意料地

例句与用法：

She soon gets out of temper if things do not go as she would like them to.

如果事情没有像她所希望的那样发展，她就会马上发脾气。

详细释义：

意外地

John arrived out of the blue.

约翰出人意料地来了。