give the game away

US /ɡɪv ðə ɡeɪm əˈweɪ/
UK /ɡɪv ðə ɡeɪm əˈweɪ/
"give the game away" picture
1.

泄露秘密, 暴露真相

to reveal a secret or surprise, often unintentionally

:
Don't give the game away by telling her about the surprise party.
不要告诉她惊喜派对的事,以免泄露秘密
His nervous laughter almost gave the game away.
他紧张的笑声差点泄露了秘密