1. Yin Jian is not far away, in the time of Queen Xia. ——Anonymous "The Book of Songs·Daya·Dang" by the Pre-Qin Dynasty

Translation: I cannot but monitor (judge) You Xia, and I cannot help but (judge) Yu Yin. It means that the descendants of Yin and Shang should take the demise of Xia as a warning, and later generally means that the lessons of their predecessors are right before their eyes.

2. Never forget the past and be the teacher of the future. ——Pre-Qin Liu Xiang's "Warring States Policy·Zhao Ceyi"

Translation: Remember the lessons of the past for future reference.

3. He who suffers a setback will benefit from it; he who experiences it will gain wisdom. ——Song Dynasty Anonymous' "Pinghua of the History of the Han Dynasty in the Five Dynasties·Han History"

Translation: After a setback, you will learn a lesson; after one thing, you will gain a point of wisdom.

4. Using the past as a mirror, we can know the ups and downs. Using people as a mirror can help you understand gains and losses. ——Wu Jing of the Tang Dynasty, "Zhenguan Politicians: Appointment of Talents"

Translation: Using history as a mirror, you can know the rise and fall of past dynasties; using people as a mirror, you can understand gains and losses.

5. If future generations grieve and fail to take note of it, it will also make future generations grieve for future generations again. ——"A Fang Gong Fu" by Du Mu in the Tang Dynasty

Translation: If future generations only know how to feel sorry for it without learning lessons from it, they will also be sympathized with by future generations.