1.The theory ofcomparative advantage
Although Smith’s work was instrumental in the development of economic theories about trade and production, it did not answer a question like if a country did not poe absolute advantage in any product, could it (or would it ) trade ?
尽管大卫李嘉图的著作在贸易和生产相关的经济理论上有指导意义，但他没有回答类似于一个国家若没有绝对优势能否贸易这样的问题。
David Ricardo (1772-1823) , in his 1819 work entitled On the Principles of Political Economy and Taxation, sought to take the basis ideas set down by Smith a few steps further.Ricardo noted that even if a country poeed absolute advantage in the production of two products, it still must be relatively more efficient than the other country in the production of one commodity than the other.Ricardo termed this the Comparative Advantage.
大卫.李嘉图在1819年的作品《政治经济学及赋税原理》，试图在斯密观点基础上进行更深一步挖掘，李嘉图表示即使一个国家在生产两种产品时有绝对优势，但相对另一个国家生产同类产品它依然有相对较高效率的产品，李嘉图把这称之为比较优势。
2.Definition
a.According to the theory of comparative advantage, it makes sense for a country to specialize in the production of those goods it produces most efficiently and to buy the goods from other countries that it produces le efficiently, even if this means buying goods from other countries that it could produce more efficiently itself.
根据比较优势理论，一个国家专注于生产那些有较高效率的产品何从其他国家购买本国生产效率相对较低的产品，即使这意味着从国外购买更高效率的产变得合情合理。 b.A country has a comparative advantage in producing a good if the
opportunity cost of producing that good in terms of other goods is lower in that country than it is in other countries.
就产品而言，如果一个国家生产这种产品相比其他国家有更低机会成本就称之为这个国家有比较优势。
3.Chief points of view
a.Each country would then poe comparative advantage in the production of one of the two products, the le efficient nation should specialize in and export the good in which it is comparatively le inefficient ( where its absolute disadvantage is least).
每个国家在生产一两种产品上有比较优势，一个生产效率相对较低的国家应专业化出口相对来说具有优势的产品。
b.The more efficient nation should specialize in and export that good in which it is comparatively more efficient ( where its absolute advantage is greatest ).And both countries would then benefit by specializing completely in one product and trading for the other.
一个相对生产效率较高的国家应专注看相对生产效率更高（绝对优势最大的）产品，这样两类国家都能从完全专业化的生产和贸易中获利。
c.Absolute productive efficiency was thus not a crucial factor governing the basis for international trade, according to Ricardo.The Ricardian model or principle of comparative advantage is today the most famous and influential principle of economics.
根据李嘉图的观点，绝对生产效率并不是控制国际贸易基础一个关键因素。李嘉图模型或相对比较优势的原理是今天经济理论中最著名的也是最有影响力的经济理论。
4.Comparison between the two Theories
a.After comparison we’ll find Ricardo’s theory of comparative advantage is more advanced than Smith’s theory of absolute advantage.在比较后我们发现李嘉图的比较优势理论比斯密的绝对优势理论更先进。 b.According to Smith’s view, the product exported by a country must be goods which the exporting country has absolute advantage to produce and the cost of producing it must be absolutely lower than the same good of another country.
根据斯密的观点，一个国家出口的产品一定是出口该国生产商有绝对优势的相比另一个国家绝对生产成本更低的产品。
c.But David Ricardo took Adam Smith’s theory of absolute advantage one step further.In his opinion not necearily every country has to produce all sorts of goods.What a nation should do is to concentrate its efforts and resources on producing those goods which can generate more advantages and bring about le disadvantages.
但是李嘉图是在斯密绝对优势理论的基础上进一步延伸的。在他看来，每个国家没必要生产所有类型的产品，一个国家需要做的只是集中精力和资源生产那些有更少劣势更多优势的产品。
d.Under such conditions international trade would result in international division of labor and specialization beneficial to all countries.In addition, Ricardo particularly streed labor productivity and argued that differences in labor productivity between nations underlie the notion of comparative advantage.
在这些条件下，国际贸易会产生国际劳动、专业分工，对所有国家都有利，除此之外，李嘉图特别强调，不同国家劳动分工、生产差异构成的比较优势。
e.Despite the differences between the two theories they have something in common.Both Smith and Ricardo emphasized the supply side of the market and the fact that the immediate basis for trade stemmed from cost differences.Actually Ricardo’s theory of comparative advantage was developed on the basis of Smith’s theory of absolute advantage.
尽管这两个理论有差异但也存在共性。李嘉图和斯密都强调了市场的供给
方，贸易基础根源于生产成本的差异，确切的说，李嘉图的相对比较优势理论是在史密斯的绝对优势理论的基础上发展起来的。
5.A questiontodiscu
A profeor is prepared to write a book.He is faster both in writing and collecting data than others.Suppose that he need 1 year to write a book, 4 months to collect data.And the student need 2 years to write a book, 6 months to collect data.But the profeor paidto his students for collecting datafor him instead of collecting data himself.
Explain the reason.
一个教授准备写一本书，他在写书和收集书籍上都比别人快，假设他需要一年去写一本书，四个月收集数据，学生需要两年写一本书，六个月收集数据，但是教授支付费用给他的学生请学生代替他自己收集数据，请解释理由。
相对学生来说，教授在写书有比较优势；相对教授来说，学生在搜集数据上更有优势。
