赵坚(左)，教授，北京交通大学经济管理学院。

Zhao Jian (left), professor at School of Economics and Management, Beijing Jiaotong University.

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赵坚(左)，教授，北京交通大学经济管理学院。

Zhao Jian (left), professor at School of Economics and Management, Beijing Jiaotong University.

youdao