存在的三个等级
Three levels of existence
以上为机器翻译结果，长、整句建议使用 人工翻译 。
不同层次的口岸因对外航线结构不同而在功能上存在较大差异，进而形成了三个等级的港势地位。
Treaty ports of different levels varied greatly in functions due to their outer shipping lines, and caused 3 kinds of harbor potential gap to come into being.
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