With the rapid development of China's economic and expansion of cities, development of underground space has become a major problem for solve urban traffic.

随着我国经济的飞速发展，城市规模的不断扩大，开发地下空间已经成为了解决城市交通问题的主要手段。

youdao

With the rapid development of China's economic and expansion of cities, development of underground space has become a major problem for solve urban traffic.

随着我国经济的飞速发展，城市规模的不断扩大，开发地下空间已经成为了解决城市交通问题的主要手段。

youdao