I don't have to tell you how important it is for you to keep your mouth shut about all this.

我不必告诉你对这件事保密有多么重要。

《柯林斯英汉双解大词典》

So learn to keep your mouth shut.

学会闭上你的嘴巴。

youdao

Never miss the chance to keep your mouth shut l.

决不要失去守口如瓶的机会。

youdao

They warn that "a health care crisis is not the time to keep your mouth shut, " but rather a critical time to speak up and be your own advocate.

WSJ: The Health Reader: Listen Up, Doc

Any Slingbox model will get the job done, and other than that, you basically just have to be able to keep your mouth shut, fill out some forms, and enjoy plenty of placeshifted teevee.

ENGADGET: SlingPlayer Mobile for Symbian in private beta Mobile