"Do you think that I'm stupid?" Which isn't really a question that he wants nor needs answered, but his anger is, as always, getting the better of him. This is just like walking in on Lan Wangji walking around with cat ears, but -

Jiang Cheng is not stupid. He recognises Chenqing. It's almost as if he had spent sixteen years worshipping the stupid flute, keeping it clean, looking after it, looking at it almost too much between paperwork and raising a child...

He wishes he could break some sense into Wei Wuxian, but not even threats would work these days.

"Of course I could understand what you said!"