If you are an ordinary person, you can't feel the flow of time at all. Even if you look at a clock and watch and know that time flows forward in a minute, you can't say that you feel the flow of time.

it's like people are in the air, but if it's not windy, who can feel the air?

but old Zhu is not the same. I don't know if it's because of the time gear tattoo on his lower abdomen. Old Zhu can clearly detect the flow of time. He can say at a glance whether the time is accelerating the flow or being still. It's quite mysterious....