In the sentence "The locks and keys of the two Beijing cities are unparalleled", which two Beijing cities do you mean?

Two Beijing: Since the Han and Tang Dynasties, Chang 'an and Luoyang have been called two Beijing.

1, the original sentence: The lock and key of the two capitals are unparalleled, and the Great Wall of Wan Li is the first pass.

2. The first pass: Shanhaiguan is the eastern starting point of the Great Wall of Wan Li and the most famous pass. Therefore, it is called "the first level".

3. Sentence meaning: Shanhaiguan is located between Shenyang outside Shanhaiguan and Beijing inside Shanhaiguan, which plays an extraordinary role in the military. Besides, nothing can compare with it. It's really the first pass of the Great Wall in Wan Li!

Step 4 enjoy

Shanhaiguan is an important pass at the eastern end of the Great Wall. It is located in the northeast of Qinhuangdao today, bordering Yanshan Mountain in the north and Bohai Sea in the south, hence the name. It is said that when Xu Da, the king of Zhongshan in the Ming Dynasty, built the Great Wall here, he first set up this pass, making it the dividing line inside and outside the pass. This pass is a magnificent tower building with four doors. The East Gate is called "the first pass in the world", and the inscription of Xiao Xian, a scholar of Ming Dynasty, hangs on the tower. This couplet is a concise and vivid introduction and description of Shanhaiguan.

"Locking the key between the two capitals" shows the extreme military importance of Shanhaiguan and highlights its special position as a gateway, which leads to the evaluation of "unparalleled place", which is reasonable. Especially the nickname "key". In this way, the first half naturally leads to the "ten thousand", "long" and "first" in the second half, and is expelled layer by layer, further revealing the unique momentum and charm of Shanhaiguan. In this way, the relationship between up and down links is causality, thus expressing the author's praise for Shanhaiguan.