# 01**Perfect Competition**
画面：左边大字号显示**Perfect Competition的定义；右边依次出现Perfect Competition的特征（如下）**
- **Number of Firms**: Many sellers and buyers.
- **Product Type**: Homogeneous products (identical).
- **Barriers to Entry**: No barriers; easy entry and exit.
- **Price Control**: Firms are price takers; they cannot influence market price.
- **Long-Run Profit**: Normal profits; no economic profits in the long run.
- **Example**: Agricultural products like wheat and corn.
画外音：对**Perfect Competition的定义和特征进行逐一介绍**
# 02**Monopolistic Competition**
画面：左边大字号显示**Monopolistic Competition的定义；右边依次出现Monopolistic Competition的特征（如下）**
- **Number of Firms**: Many sellers.
- **Product Type**: Differentiated products (similar but not identical).
- **Barriers to Entry**: Low barriers; entry and exit are relatively easy.
- **Price Control**: Some degree of price-setting power due to product differentiation.
- **Long-Run Profit**: Typically, only normal profits in the long run due to competition.
- **Example**: Restaurants, clothing brands.
画外音：对**Monopolistic Competition的定义和特征进行逐一介绍**
# 03**Oligopoly**
画面：左边大字号显示 **Oligopoly的定义；右边依次出现 Oligopoly的特征（如下）**
- **Number of Firms**: Few large sellers.
- **Product Type**: Can be homogeneous (like steel) or differentiated (like cars).
- **Barriers to Entry**: High barriers to entry (e.g., capital costs, patents).
- **Price Control**: Significant price-setting power; firms often engage in strategic behavior, such as price-fixing or collusion.
- **Long-Run Profit**: Can earn economic profits due to market power.
- **Example**: Automobile manufacturers, airlines.
画外音：对**Oligopoly的定义和特征进行逐一介绍**
# 04**Monopoly**
画面：左边大字号显示 **Monopoly的定义；右边依次出现 Monopoly的特征（如下）**
- **Number of Firms**: One seller in the market.
- **Product Type**: Unique product with no close substitutes.
- **Barriers to Entry**: Extremely high barriers (legal, market, or technological).
- **Price Control**: Significant price-setting power; monopolist can influence market price.
- **Long-Run Profit**: Can earn sustained economic profits.
- **Example**: Utility companies, patent-protected drugs.
画外音：对**Monopoly的定义和特征进行逐一介绍**
# 05Summary table
画面：居中出现一个summary table（放大一点）
| **Characteristic** | **Perfect Competition** | **Monopolistic Competition** | **Oligopoly** | **Monopoly** |
| --- | --- | --- | --- | --- |
| Number of Firms | Many | Many | Few | One |
| Product Type | Homogeneous | Differentiated | Homogeneous/Differentiated | Unique |
| Barriers to Entry | None | Low | High | Very High |
| Price Control | Price takers | Some price-setting power | Significant | Price maker |
| Long-Run Profit | Normal profits | Normal profits | Economic profits possible | Economic profits |
| Example | Agricultural products | Restaurants | Automobile manufacturers | Utility companies |
画外音：对这个表中比较重要的内容进行强调讲解
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Perfect Competition is a market structure characterized by many firms competing with identical products. Let me explain its key features. First, there are many sellers and buyers in the market. Second, all products are homogeneous or identical. Third, there are no barriers to entry or exit. Fourth, firms are price takers and cannot influence market price. Fifth, firms earn only normal profits in the long run. Finally, examples include agricultural products like wheat and corn.
Monopolistic Competition is a market structure where many firms compete with differentiated products. Let me explain its key characteristics. First, there are many sellers in the market. Second, products are differentiated, meaning they are similar but not identical. Third, barriers to entry are low, making entry and exit relatively easy. Fourth, firms have some degree of price-setting power due to product differentiation. Fifth, firms typically earn only normal profits in the long run due to competition. Examples include restaurants and clothing brands.
Oligopoly is a market structure dominated by a few large firms with significant market power. Let me explain its key characteristics. First, there are only a few large sellers in the market. Second, products can be either homogeneous like steel or differentiated like cars. Third, there are high barriers to entry such as capital costs and patents. Fourth, firms have significant price-setting power and often engage in strategic behavior such as price-fixing or collusion. Fifth, firms can earn economic profits due to their market power. Examples include automobile manufacturers and airlines.
Monopoly is a market structure where a single firm controls the entire market. Let me explain its key characteristics. First, there is only one seller in the market. Second, the product is unique with no close substitutes. Third, there are extremely high barriers to entry, whether legal, market-based, or technological. Fourth, the monopolist has significant price-setting power and can influence market price. Fifth, monopolies can earn sustained economic profits. Examples include utility companies and patent-protected drugs.
This summary table compares the four main market structures across key characteristics. Perfect Competition has many firms with identical products and no barriers to entry, making firms price takers with normal profits. Monopolistic Competition also has many firms but with differentiated products, giving some price-setting power. Oligopoly features few large firms with high barriers and significant market power, allowing economic profits. Monopoly represents the extreme with one firm, unique products, very high barriers, and sustained economic profits. Understanding these differences helps analyze real-world markets and their competitive dynamics.