Sanyu: refers to what Dong Yu said: "Winter is a year's free time, night is an extra time in a day, and rainy days are always extra time." You can study hard.
Five cars and eight fights: two idioms: learning to be rich and five cars, a man of great talent. It means reading five cars full of books; The talent of people all over the world is compared to "a stone (a burden to study)", accounting for eight of them (80%). Together, the two idioms mean high learning.
Four books: University, The Doctrine of the Mean, The Analects of Confucius and Mencius.
Four histories: Historical Records, History of Han, History of Later Han and History of the Three Kingdoms, which belong to the first four of the twenty-four histories and usually refer to all historical documents.
Thousands of households are divided into thousands of points: enjoy high officials and generous salaries. Thousands of households, ancient official positions, here refers to officials. Wanling is a quantifier and a unit of measurement for grains. Wanling refers to many grains. In ancient times, grain was the salary, and many grains meant "high salary".