C861 The Man Behind the Black Gourd

"Thank you for your advice, Madam Yuan!"

Lee Yixuan immediately expressed his gratitude.

"I'm just giving you a simple hint. If you don't know how to change the frequency, you won't be able to learn it even if I teach you."

Madam Yuan's words were true. Lee Yixuan seemed to be able to do it easily, but if it was anyone else, they might not be able to do it for the rest of their lives