Chu Chu looked speechlessly at Chu Mo: "Not calculated by age?"
Chu Mo had a profound look: "What is time?"
The field of time is quite profound; even Dao-converting cultivators find it hard to grasp the mysteries contained within the world completely. So, when Chu Mo threw this question out, it made Chu Chu dumbfounded for a while before she said: "Time... is naturally the passage of years. It's a process. For instance, I've grown from a child to adulthood, how many days did it take..."
At this point, Chu Chu found it hard to continue.
Because the concept of "days" varies between different universes!
For example, here in the Tunnel, a day is quite lengthy.
Above the skies of the Tunnel, there are numerous suns. The term sun actually refers to all stars that can emit heat.
The concept of a day involves the sun rising, setting, and rising again, which counts as a day. But in different places, the length of a day is definitely different.