犯罪大师秦淮行答案

This formation was at the fourth level, and Ning Cheng couldn't set it up even at his own expense. The reason why he could tell that it was a concealment formation was because it was already somewhat broken. If this formation is not broken, Ning Cheng suspects that this formation even exceeds the seventh level. If it was really a formation above level seven, he wouldn't even be able to tell....