Cold joke, why does Tang Priest want to learn from the scriptures?

When Tang Priest said goodbye to Emperor Taizong, he promised to return to Emperor Taizong three to five years later, but he didn't know it would take fourteen years.

Li Shimin: "Jade Emperor, why did you come back after so many years? Didn't you say you would come back in three to five years? "

Tang Priest: "Your Majesty, you don't know. 1 1 month 1 day and may1day, the highways in Spring Festival travel rush are crowded with dogs. "

Li Shimin: "There are only a few legal holidays. What about other times? "

Tang Priest: "It's not a legal holiday. If the highway is not free, how can we afford it! "

Li Shimin: "..."