List three scientific and technological developments in Han Dynasty to improve production efficiency, four famous generals who fought against Xiongnu, and five idioms related to Qin and Han Dynasties. Thank you~ Three scientific and technological developments to improve production efficiency:

1. During the reign of Emperor Wu of the Han Dynasty, water conservancy was built, and Cao Canal, Liu Auxiliary Canal, Bai Canal, Chengguo Canal, Luoshou Canal and Longshou Canal were built, which promoted the development of agricultural production;

2. When Emperor Xuandi was proclaimed in the Han Dynasty, the grain transportation was reformed vigorously, and * * * 3, grain soldiers in Kanto were saved;

3. During the reign of Emperor Han Ming, the "fake public land" was implemented, and the state-controlled wasteland Chuanze was leased to the poor and refugees, which promoted social progress.

Four famous generals who fought against the Huns:

Wei Qing, Huo Qubing, Li Guang, Gong Sunhe, Wang Hui, Han Anguo and so on.

Five idioms related to the Qin and Han Dynasties:

Han Xin ordered more troops, the more the better, the more the sand, the more the water, the half-way crossing, the last stand, the flag-pulling, the easier it is to die, and the later life, the clear path, the secret crossing, the humiliation of the legs, the contribution of Gao Zhen, the embattled, and the ten-mile ambush.