參考答案:

The Great Wall was built to defend against the northern invaders from Mongolia. Smaller and shorter walls had been built over the years, while Qin Shi Huang decided to build a single giant wall to protect his northern borders. The construction of the Great Wall started in the Qin Dynasty and the following dynasties continued to work on it Later, the Ming Dynasty rebuilt the wail Most parts of the so- called Great Wall today was built in the Ming Dynasty. The wall was built by peasants,slaves, criminals, and other people that the emperor decided to punish.

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