[资料]2歇息临盆率和比拟上风：李嘉图模型.ppt

YOU ARE WELCOME !;International Economics;Chapter 2;Preview;Countries engage in international trade for two basic reasons: They are different from each other in terms of climate, land, capital, labor, and technology. They try to achieve scale economies （规模经济）in production. The Ricardian model is based on technological differences across countries. These technological differences are reflected in differences in the productivity of labor.;The Ricardian model uses the concepts of opportunity cost and comparative advantage.;For example，On Valentine’s Day the U.S. demand for roses is about 10 million roses. Growing roses in the U.S. in the winter is difficult. Heated greenhouses should be used. The costs for energy, capital, and labor are substantial. Resources for the production of roses could be used to produce other goods, say computers.;Opportunity Cost（机会成本） The opportunity cost of roses in terms of computers is the number of computers that could be produced with the same resources as a given number of roses. Comparative Advantage（比较优势） A country has a comparative advantage in producing a goods if the opportunity cost of producing that goods in terms of other goods is lower in that country than it is in other countries. 如果一个国家在本国生产某种产品的机会成本（用其他产品来衡量）低于在其他国家生产该种产品的机会成本的话，则这个国家在该种产品的生产上具有比较优势。;Suppose that in the U.S. 10 million roses can be produced with the same resources as 100,000 computers. Suppose also that in South America 10 million roses can be produced with the same resources as 30,000 computers. This example assumes that South American workers are less productive than U.S. workers. ;If each country specializes in the production of the goods with lower opportunity costs, trade can be beneficial for both countries. Roses have lower opportunity costs in South America. Computers have lower opportunity costs in the U.S. The benefits from trade can be seen by considering the changes in production of roses and computers in both countries.;Table 2-1: