摘要
A very popular Chinese song goes, "the Great Wall is ten thousand li (one li=1/2 kilometer) long, and at the foot of it is my homeland...." It always moves the Chinese who live overseas to tears. In Chinese’s hearts, the Great Wall is a symbol of the Chinese nation. The construction of the Great Wall can be dated back to the Spring and Autumn Period and the Warring States Period in the 7th and 8th century (B.C), when different states in the
