a cool head

基本解释

Keep a cool head when thing go wrong.
出問題時要保持冷靜的頭腦。
The device, a prototype of which was unveiled this week, is an emotion-sensing system designed to help investors keep a cool head when buying and selling.
剛於本周公佈的這項設備的雛形，是一個情緒感知系統，旨在幫助投資方在買賣時，保持冷靜。
One could argue that he thrives off that fire in his belly, but at the same time he is supposed to be the finisher, and often the creator, which calls for a cool head.
有人可能會說這是這種高昂的鬭志成就了魯尼，不過同時他在球場上大多數時候很可能即是最後一腳的完成者，也是機會創造的組織者，不過不論是做哪一個都需要冷靜的頭腦。

"There is no pressure. I have gone through pressure up to this time, so I need a cool head.

You'll need a cool head if the bidding gets overheated, but the boats have clear title.
FORBES: Boat Bargain
Neil will tell us how to profit by keeping a cool head while the markets panic.
FORBES: Steve Forbes Interviews Neil Hennessy
As the chairman knows well, he must always keep a cool head even as others lose their shirts.
ECONOMIST: And Ben Bernanke keeps his cool