1, Xu Shu entered Cao Ying's next sentence: Don't say anything.

2. "Xu Shu entered Cao Ying without saying a word" is an allusion from the literary work Romance of the Three Kingdoms. Xu Shu became Liu Bei's strategist by introducing himself, but was deceived to Cao Ying by Cao Cao's counselor Cheng Yu. After that, Cao Caobing attacked Fancheng where Liu Bei was stationed. At Ye Liu's suggestion, Cao Cao sent Xu Shu to Fancheng to persuade Liu Bei to surrender, but after Xu Shu arrived in Fancheng, he told Liu Bei that the army was coming and told Liu Bei to prepare early.

3. Liu Bei wanted to keep Xu Shu, but Xu Shu refused on the grounds that Liu Bei was assisted by Zhuge Liang, fearing that everyone would laugh at him, and told Liu Bei that although he was in Cao Ying, Cao, he vowed not to offer a plan for Cao Cao Ying. After the events of "Xu Shu entered Cao Cao camp" and "Guan Yu surrendered to Cao Cao", it evolved into the idiom "Being in Cao Cao camp and being in Han Dynasty".