The decision came out of the blue.

这个决定来得很突然。

《牛津词典》

"I want to talk to my wife," Donald Herbert said out of the blue.

“我想和我的妻子谈谈。”唐纳德·赫伯特突然说道。

youdao

About 15 minutes down the motorway, out of the blue, he announced that I was heading in the wrong direction for Weymouth.

在高速公路上开了大约15分钟后，他突然宣布我往错误的方向去了韦茅斯。

youdao

"Most of the fish,shrimp, blue crab they are spawning out in the Gulf right now, and any of those really small larvae fish and crab, is probably going to be killed if they encounter the actual oil spill."

VOA: standard.2010.07.13

I was taking my younger child home from a play date on Sunday and he asked me out of the blue, ?" "Why can't you marry your mother or your father?"

周日我带我的小儿子去玩，回家的路上,他突然问我，“你为什么不能和你的父母结婚“

耶鲁公开课 - 心理学导论课程节选

and I kind of want to go somewhere that's just out of the blue that I never even thought of,

我想去意想不到的地方，自己根本没想过的，

为我的生活 - SpeakingMax英语口语达人

What would you do if your responsibilities at work radically changed out of the blue?

FORBES: What To Do When They Radically Change Your Job

Maybe the concept came to you in a flash, the proverbial bolt out of the blue.

FORBES: You Have THE BIG IDEA, What Do You Do Next?

Then, out of the blue, her lonely birth-mother, Ellen, contacts the daughter given up at birth.

ECONOMIST: Memoirs of adoption