Limitations of Classical theory:
1. Assumption of full employment: Classical theory assumes that there is always full employment in the economy. However, in reality, there is often unemployment or underemployment due to various factors such as technological changes, economic recessions, and labor market imperfections.

2. Failure to consider economies of scale: Classical theory does not take into account the concept of economies of scale, which refers to the reduction in average costs that occur as a firm increases its scale of production. This omission limits the theory's ability to explain the pattern of trade between countries with different levels of economic development.

3. Lack of consideration for transportation costs: Classical theory assumes that transportation costs are negligible or do not exist. In reality, transportation costs play a significant role in determining the pattern of trade between countries. The theory fails to consider how transportation costs affect the comparative advantage of countries in producing and trading goods.

4. Limited focus on labor theory of value: Classical theory is based on the labor theory of value, which states that the value of a good is determined by the amount of labor required to produce it. However, this theory oversimplifies the factors that determine the value of a good in a market economy, such as supply and demand dynamics, technology, and resource availability.

Differences between Ricardian theory and Classical theory:
1. Comparative advantage: The Ricardian theory of international trade is based on the principle of comparative advantage, which states that countries should specialize in producing goods in which they have a lower opportunity cost compared to other countries. In contrast, the Classical theory focuses on absolute advantage, which states that countries should specialize in producing goods in which they have an absolute advantage over other countries.

2. Role of technology: Ricardian theory recognizes the role of technology in determining comparative advantage. It assumes that technology is fixed and does not change over time. In contrast, Classical theory does not consider the role of technology in determining comparative advantage.

3. Labor theory of value: Ricardian theory is based on the labor theory of value, similar to the Classical theory. However, Ricardian theory recognizes that the value of a good is determined not only by the amount of labor required to produce it but also by the relative productivity of labor in different industries.

4. Trade patterns: Ricardian theory explains the pattern of trade between countries based on comparative advantage, while Classical theory focuses on absolute advantage. As a result, Ricardian theory provides a more nuanced explanation of the gains from trade and the basis for specialization between countries.

In conclusion, while Classical theory provides valuable insights into international trade, it has several limitations that restrict its ability to explain real-world trade patterns. The Ricardian theory, on the other hand, addresses some of these limitations by introducing the concept of comparative advantage and considering the role of technology and relative productivity in determining trade patterns.