They keep that night a special secret which makes them feel even closer to each other.

那天晚上的事成了他们的秘密,这让他们觉得彼此更亲近了。

耶鲁公开课 - 心理学导论课程节选

I'm going to keep this secret like a good friend.

我会像一个好朋友那样严守秘密。

That's all实战 - SpeakingMax英语口语达人

How to gain, how to keep, how to recover happiness, is in fact for most men at all times the secret motive of all they do, and all they are willing to endure."

如何获得，如何保持，如何重获快乐，是多数人时刻怀有的秘密动机，是他们愿意忍受一切的目的“

哈佛公开课 - 幸福课课程节选

I promised Sarah that I was going to keep it a secret.

我答应Sarah我会严守秘密的。

I can't 实战 - SpeakingMax英语口语达人