C502 Tell me why?

"Clang ?" Bing Ying suddenly smashed hard onto the bed wall beside him.

A bizarre sound echoed, and Zhang Xuan's eyebrows knitted together.

During the night, the things that rapidly slipped through his mind and then disappeared, now gradually combined together ?

"Knock, knock ?" Bing Ying raised his hand again and knocked twice more.

Yes, indeed.

So that's how it is