Question

i heard it through the grapevine that you were having a surprise party for me. it looks like someone could not ______.

get the ball rolling

face the music

hold their tongue

Explanation:

To solve this, we analyze the context and the meaning of each idiom:

• "get the ball rolling" means to start an activity. This doesn't fit as the issue is about someone revealing the surprise.
• "face the music" means to accept the consequences of one's actions. This is not relevant to the context of revealing a secret.
• "hold their tongue" means to keep quiet. Since the surprise party was revealed (the speaker heard about it), it means someone couldn't keep quiet, so this idiom fits.

Answer:

hold their tongue