The Scum Is Realist

"Yes. I haven't taught Ling Yun about this yet." Cheng Sheng nodded in affirmation of what Lei Ling has said.

It is not that he didn't have the intention of not teaching Ling Yun about this topic. He took Ling Yun as his disciple, so why would he not teach Ling Yun? The problem is that the time that they spent with each other as a teacher and his disciple is short, since he has accepted Ling Yun just recently. Not to mention that he wanted to teach Ling Yun first the practical things that he needed to know and to use it during this crisis so that while he learns, he could also help his sect, as well as contribute to their land. 

So, he hasn't taught Ling Yun about distinguishing the types of spiritual energy yet. Now, it turns out that he needed to do so. They have to sped up, so that they won't fall for the enemies' tricks twice.