1. Confucius said: "Isn't it right to say that when one learns and practices from time to time? Isn't it a joy to have friends come from afar? If someone doesn't know and is unhappy, isn't that a gentleman?" ("Learning and practicing") 》)

Explanation: Shi: on time; said: same as "joy", happy.

Translation: Learning requires constant review to master. After learning knowledge, review on time, this is Pleasant things. There are both learning methods and learning attitudes. Friends here refer to like-minded people. It is a pleasure to have like-minded people come from afar to discuss issues together.

Appreciation: People I don't understand, but I don't resent it. This is the style of a gentleman. This is about personal cultivation.

2. Confucius said: "Those who review the past and learn the new can become a teacher." ("Wei Zheng")

Explanation: Therefore: old (knowledge); Zhi: understanding, comprehension.

Translation: Review old knowledge, and gain new understanding or discovery from it. In this way, You can become a teacher.

3. Confucius said: "Learning without thinking leads to leap; thinking without learning leads to peril." ("Wei Zheng")

Explanation: 罔: Confused but without gain; Peril: Mentally tired but without gain.

Translation: If you just read without thinking, you will feel confused; if you just dream without reading, you will have doubts.

Appreciation: This article explains the dialectical relationship between learning and thinking, and also talks about learning methods.