Keep your mouth shut.
跟任何人說都不行。/這是秘密。

A:I heard Beth's surprise birthday party is on Sunday.
我聽說貝絲的生日驚喜派對定在星期天了。

B:Keep your mouth shut about that.I don't want her to find out.
千萬保密，我不想讓她知道。

英英釋義：

This means "Don't tell anyone." It is said when there is a secret to be kept.

美劇表達：

1.You keep your mouth shut unless I give you permission to open it. Understand?
得到我允許之前，你一定要守口如瓶，明白嗎?

2.You keep your mouth shut.No one here cares what you think!
不要說了，沒人對你的想法感興趣!

3.You keep your mouth shut about the ring.
不能跟人說起這枚戒指的事。

Keep this to yourself.
這是秘密。/你一個人知道就行了。/別對任何人講。

A:Keep this to yourself.I'm planning to retire.
別對人說，我打算退休了。

B:But the company needs you here to run things.
但是公司需要你留下來繼續工作。

英英釋義：

This usually means something is private.It is like saying "Please don't tell anyone else."

美劇表達：

1.You keep this to yourself while we work it out.
在我們解決問題期間，這件事情只能你一個人知道。

2.You keep this to yourself! Not a word. We do not speak of this again. You understand?
這可是秘密，不要透露半個字!我們也不會再提起，明白嗎?

The cat's out of the bag.
秘密被揭穿了。

A:That movie star and his wife are divorcing.
那個電影明星和妻子正在鬧離婚。

B:The cat's out of the bag. Now everyone knows.
消息已經傳開了，大家都知道了。

英英釋義：

This indicates "Someone told the secret." Often it is a way to say now many people know the secret.

美劇表達：

1.Oh, great. Now the cat's out of the bag.
噢，太棒了，現在秘密已經被揭穿了。

2.Oh, you might as well tell her.
你還是告訴她吧。

（來源：可可英語? 編輯：Julie）