Waiting Online: Traveling to Another World in One Day, Urgent!

[Determined to kill, invincible to the lowest, all over the world, light dog food, dark, single female protagonist] A countdown suddenly appeared in Su Bai's mind, telling him that he would travel to a different world of horror and resurrection in one day! He directly posted a message on Zhihu asking for help, and experts offered suggestions one after another! In the end, Su Bai traveled across time with ten kilograms of books! Everything from steelmaking, thermal weapons, shipbuilding, steam engines and other technologies... After traveling through time, Su Bai was confused! At that moment, he had the urge to pick up the book and travel back in time! What's even more outrageous is that he feels that his frog cub is very improper! Just forget about stealing KDA Ahri at the beginning... I never brought back a normal thing!