Rebirth of Li Chengqian and Build the First Empire

When Li Chengqian woke up, he found that a memory about the 21st century suddenly appeared in his mind. What? The average life expectancy of the people of the Tang Dynasty was short, so medicine should be developed and rural medicine should be promoted. What? If the horse runs slowly, then go dig coal and build a steam engine. What? My father wants to depose me. I'm sorry, my father, I know you want to abdicate, so let your son suffer the pain of loneliness for you!