C80 I Formally Invite You to Join

"Hey, old man, how could I bring someone who's not too tough to your place?"

"So, this is your favorite student?" The old man raised an eyebrow. "Come on, young man. I'll test you."

Kang Yushuang smiled, "You give me a question."

"Whoa, brat, you're quite calm. You better be careful, I'm not your teacher. I have to be responsible for my patients, so I can't give you water. If you pass my test