I had no idea in Spanish

When to use it: Say this when you learn something that was completely unknown to you.

Tenía is the past form of tener here; learn the whole chunk as one reaction.

Say it: teh-NEE-ah ee-DEH-ah

When to use it: Use this when someone tells you a fact you did not know.

Sabía means I knew in the past; eso points back to the information you just heard.

Say it: ah, noh sah-BEE-ah EH-soh

When to use it: Say this when news sounds surprising, impressive, or hard to believe.

Qué means what here, but the full expression means that's amazing.

Say it: keh een-kreh-EE-bleh

When to use it: Use this when you need someone to stop and clarify something surprising.

Espera is an informal command meaning wait; the question asks for clarification.

Say it: ehs-PEH-rah, keh

When to use it: Use this pattern when you are shocked by what a named person did.

Replace the blank with a person's name; hizo means did for one person.

Say it: EE-soh keh