International economics

Labor, land, recession and improvement.

Explanation: The answer can be extended in the Heckschel-Olin model (that is, the factor proportion model): in trade and income distribution, the owners of rich factors in China benefit from trade, while the owners of scarce factors suffer losses from trade (relative).

You can understand it by knowing the factor proportion model. If you don't know, you need to understand this model. This model is very long. You can go to Baidu yourself or go to the library to find books on international economics.