有一天，她毫无预兆地宣布她要离开。

One day, ___out ___of ___the ___blue, she announced that she was leaving.

当我意外收到你的来信时，我高兴极了。

I was extremely happy when I received your letter ___out ___of ___the ___blue.

这个工作机会来得非常意外，彻底改变了他的职业规划。

The job offer came ___out ___of ___the ___blue, completely changing his career plans.