Second, a hundred schools of thought contend:

3. Establishment of centralization in Qin Dynasty: From 230 BC to 22 BC1year, Ying Zheng, king of Qin, destroyed six countries and established the first unified and centralized feudal country in China history-Qin Dynasty.

Fourth, 1, Qin Shihuang's measures to consolidate reunification:

Six, Liang Wudi's unified measures:

Seven, western settings:

Eight, the Silk Road:

Nine, papermaking:

Zhang Heng (Eastern Han Dynasty) Seismograph: the earliest instrument in the world to determine earthquake orientation;

Xi。 Sima Qian and Historical Records: He lived in the period of Emperor Wu of Han Dynasty and was a great historian in ancient China. Historical Records is the first biographical general history in China, which records the history from Huangdi to Emperor Wudi of the Han Dynasty and establishes the biographical style. It is not only a historical work, but also a literary work.

Twelve. Battle of Red Cliffs:

13, 230, Sun Quan sent general Wei Wen to Yizhou, which strengthened the connection between the mainland and Taiwan Province Province.

Fourteen Reform of Emperor Xiaowen in Northern Wei Dynasty;

15. Mathematical achievements: Zu Chongzhi (Southern Dynasties): For the first time in the world, the value of pi was accurate to the seventh place after the decimal point, which was nearly 1000 years earlier than that in Europe.

There are too many answers upstairs! I can't take that many exams at all! !