secret

我们试图在妈妈生日前对她保密这个惊喜派对。

We tried to keep the surprise party ___secret from Mum until her birthday.

我正在为他举办一个派对，但这是个秘密。

I'm having a party for him but it's a ___secret.

你能保守一个秘密吗？

Can you keep a ___secret?