A history of China is a history of the Chinese nation, a history in which all ethnic groups blend and converge into a pluralistic whole, and a history of the great motherland jointly created, developed and consolidated by all ethnic groups. China has been a multi-ethnic country since ancient times, and China's unity and vast territory were jointly created and developed by all ethnic groups in China. The cultural history of China was also jointly created by 56 ethnic groups in China and their ancestors in the development process of thousands of years. Among them, the Han nationality is in the dominant position, and all ethnic minorities have made their own contributions. After thousands of years of splendid ancient agricultural civilization, China society slowly developed to the Qing Dynasty. At this time, great changes have taken place in China and the world, and the so-called "unprecedented changes" have appeared. This change has put forward two very serious and urgent new historical issues for the people of China, namely: resisting foreign aggression and striving for the independence of the country and the nation; Conform to the trend of world modernization and realize the overall transformation of China society. It has been more than 70 years since the founding of New China. For more than 70 years, under the leadership of the Production Party of China, the Republic of China has been making unremitting efforts and arduous explorations to achieve national prosperity and all-round social progress, to build a powerful modern country, and to realize the rejuvenation of the Chinese nation.

-Excerpted from Zhang Qizhi's Fifteen Lectures on the History of China.

Combining materials and historical facts related to China's history, I choose an angle to draw up a specific topic and elaborate the proposed topic. (It is required to state the topic, take the time sequence as the clue, combine history with theory, and express the specification. )