The sixth grade 17 class incident gave a powerful counterattack to the imperialists who despised China.

This sentence comes from Zhan Tianyou.

The Beijing-Zhangjiakou Railway was completed in less than four years, two years ahead of schedule. This incident gave a powerful counterattack to the imperialists who despised China.

-echoing the first sentence of the text.

Zhan Tianyou is an outstanding patriotic engineer in China. Under his auspices, the railway from Beijing to Zhangjiakou was successfully built for the first time.

Description ————

"Strike back" means to strike back at the attacker. Before the construction of the Beijing-Zhangjiakou Railway, the imperialists tried their best to obstruct the construction of China engineers and technicians, attacking China for appointing Zhan Tianyou to preside over the construction of the Beijing-Zhangjiakou Railway as a "joke" and even boasting that "China engineers who can build the railway north of Nankou have not yet been born". The Beijing-Zhangjiakou Railway was completed two years ahead of schedule, which proved the intelligence of the people in China, increased the ambition of the people in China and destroyed the prestige of imperialism. This period shows the achievements of the construction of the Beijing-Zhangjiakou Railway, which once again shows that Zhan Tianyou is an outstanding patriotic engineer, echoing the first sentence.