In today's primary and secondary school classes in China, plane geometry is a must for students. They use professional terms to discuss mathematical problems, such as "points", "lines", "surfaces", "parallel lines", "triangles", "quadrangles", and so on. In all walks of life, we also use these mathematical terms to solve many specific problems. The mathematical knowledge we often see comes from Euclid, an ancient Greek mathematician, and was introduced into China by Matteo Ricci, a Catholic missionary, in the Ming Dynasty. The Chinese terms used to express these concepts were established when translating the Elements of Geometry. It was Matteo Ricci and his Chinese student, Xu Guangqi, who translated the Elements of Geometry. It was more than 400 years ago that Xu Guangqi established these Chinese terms that affect our daily life. The statue of Xu Guangqi in Shanghai Guangqi Park. Xu Guangqi, photographed by Wu Yan, is the most peculiar and complicated person in the history of Chinese and Western transportation. He was a minister of Zaifu who was a scholar, but he often engaged in agricultural work in the field, like a farmer; He was the top civil servant of the empire, but he was committed to training troops and stationing fields and introducing western firearms, just like a military general; He gained fame by virtue of Confucianism, but his main cause was practical learning, and he was a practical scientist; He is a scholar of Confucius and Mencius, but he is keen to spread all kinds of scientific knowledge from the West and is a cultural exchange envoy. What's more, he was baptized and became a Catholic. Later, he was regarded as one of the three pillars of Chinese Catholicism, but he once served as the Minister of Rites of the Ming Dynasty. There are many conflicting elements in Xu Guangqi, but they converge harmoniously. This great achievement is enough for future generations to think deeply. In 1562, the 41st year of Jiajing in the Ming Dynasty, Xu Guangqi was born in Shanghai County, Songjiang Prefecture, Nanzhili (now Shanghai). At the time of his birth, the eastern coastal areas of China were being killed and looted by Japanese pirates, and the people suffered from war. His grandfather was engaged in business, but he died very early. When his father came, he suffered from Japanese pirates, so that he had to work as a farmer to support his family. Xu Guangqi began to study in Longhua Temple when he was 8 years old. At the age of 15, he learned from his fellow villager Huang Tiren. At the age of 20, he passed the examination of a scholar and enrolled in the official school of Jinshanwei. However, he failed in the village examination for more than ten years. It was not until 1597 that Xu Guangqi, 35, participated in the Shuntianfu provincial examination. His examination papers were picked up again by Zhang Wudian, the examiner, and recommended to Jiao Hong, the examiner. Jiao Hong looked at them and praised them and won the first place. In 1604, Xu Guangqi was selected as a junior scholar in the Imperial Academy and studied in the Imperial Academy in Beijing. The first half of Xu Guangqi's life, like many Chinese literati and officials, repeated the joys and sorrows of life in the imperial examination era. However, for Xu Guangqi, becoming a scholar was the end of the first half of his life, and he was about to start a new chapter in his life. In 1593, in order to make a living, Xu Guangqi went to Shaozhou, Guangdong Province to teach in the museum. Three years ago, Matteo Ricci moved to Shaozhou from Zhaoqing and built a Catholic church in the west of the city. Xu Guangqi, who lived alone in Shaozhou and was bored, walked to the Catholic Church in the west of the city one day after teaching, but Matteo Ricci had gone north