Common sense, in many aspects, Xu Qing was not clear whether Jiang He understood it or not, and if she did, whether her understanding was correct or mistaken.
Often, Jiang He herself wasn't sure whether what she knew was still relevant or correct in this place.
Colliding modern with ancient common sense made it difficult for her to distinguish whether what she grasped was indeed common sense, or if it was old knowledge that had been overturned.
Thus, the Forest of Dark Knowledge was born...
No matter when, whether Jiang He understood or not, as soon as Xu Qing realized something might be beyond her knowledge, he would initiate an enlightenment mode, nipping any potential hazards in the bud.
"That's why you shouldn't think that a peaceful and prosperous age means peace everywhere. Bad people will always exist, and you have to be vigilant at all times... Have you noticed you've become quite relaxed recently?"
"Have I?"