Activity Notice (Must See)

The book is coming to an end. In order to give back to the readers for their support and help in the past two years (and far more than two years), I decided to hold a feedback activity at the end, and give out some peripherals of the book by lottery (specifically to be determined).

Interested friends can join the book friend group (this book has set up a one-click group adding function) to participate in voting and lottery.

Must come duck!