Black-haired people don’t know how to study early, and white-haired people regret studying late.

The book has its own golden house, and the book has its own beauty like jade.

The lights are on at three o'clock and the chicken is on at five o'clock, which is when men are studying.

When the book is used, it will be regretted. It will not be difficult until it has happened.

Read thousands of books and travel thousands of miles.

Read it a hundred times and its meaning will become apparent.