# 01**Perfect Competition**
画面：左边居中大字号显示**Perfect Competition的定义；右边依次出现Perfect Competition的特征（整体把左右页面填充完整，不要在页面下方出现太多空白）**
- **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）（整体把左右页面填充完整，不要在页面下方出现太多空白）**
- **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）（整体把左右页面填充完整，不要在页面下方出现太多空白）**
- **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）（整体把左右页面填充完整，不要在页面下方出现太多空白）**
- **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）；对比较重要的内容用另外一种颜色显示，标粗强调
| **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 represents an ideal market structure with specific characteristics. It features many sellers and buyers trading homogeneous or identical products. There are no barriers to entry, allowing firms to easily enter or exit the market. Firms are price takers, meaning they cannot influence market price and must accept the prevailing market price. In the long run, firms earn only normal profits with no economic profits. Agricultural products like wheat and corn are classic examples of markets approaching perfect competition.
Monopolistic Competition combines elements of both monopoly and perfect competition. It features many sellers in the market, but unlike perfect competition, products are differentiated rather than identical. This product differentiation gives firms some degree of price-setting power. Barriers to entry remain low, allowing relatively easy entry and exit. Due to ongoing competition, firms typically earn only normal profits in the long run. Common examples include restaurants and clothing brands, where products are similar but not identical.
Oligopoly represents a market structure with few large sellers dominating the industry. These firms possess significant market power and face high barriers to entry, such as substantial capital requirements or patent protection. Products can be either homogeneous like steel or differentiated like automobiles. Firms have considerable price-setting power and often engage in strategic behavior, including potential collusion or price-fixing. Unlike perfect competition, oligopolies can sustain economic profits in the long run due to their market power. Classic examples include automobile manufacturers and airline industries.
Monopoly represents the extreme opposite of perfect competition, featuring a single seller dominating the entire market. The monopolist offers a unique product with no close substitutes, giving consumers no alternative choices. Barriers to entry are extremely high, whether legal, technological, or market-based, preventing any competition from emerging. As the sole supplier, the monopolist acts as a price maker with complete control over market price. This market power allows monopolies to earn sustained economic profits in the long run. Examples include utility companies and patent-protected pharmaceutical drugs.
Perfect Competition represents an ideal market structure with many buyers and sellers trading identical products. In this market, no single firm can influence prices - they are price takers. There are no barriers preventing new firms from entering or existing firms from leaving the market. Due to intense competition, firms can only earn normal profits in the long run. Agricultural markets like wheat and corn closely resemble perfect competition.
Monopolistic Competition combines elements of both perfect competition and monopoly. While there are many sellers like in perfect competition, each firm sells a slightly different product. This product differentiation gives firms some pricing power. Entry barriers are low, allowing new competitors to enter relatively easily. Examples include restaurants offering unique cuisines and clothing brands with distinct styles. Despite some market power, competition typically drives long-run profits to normal levels.
Oligopoly markets are characterized by a small number of large firms that dominate the industry. These firms have significant pricing power and often engage in strategic behavior, sometimes cooperating through price-fixing or competing aggressively. High barriers to entry, such as large capital requirements or patents, protect existing firms from new competition. Examples include the automobile industry and airline markets. Due to their market power, oligopolistic firms can often sustain economic profits in the long run.
Monopoly represents the opposite extreme from perfect competition. A single firm controls the entire market, selling a unique product with no close substitutes. Extremely high barriers prevent any competition from emerging. These barriers might be legal, like patents, or natural, like control over essential resources. The monopolist has complete price-setting power and can sustain economic profits indefinitely. Examples include utility companies and pharmaceutical companies with patent-protected drugs.
This summary table compares the four main market structures across key characteristics. Notice the clear progression from many firms in perfect competition to just one in monopoly. Product differentiation increases as we move from perfect competition through monopolistic competition. Barriers to entry become progressively higher, determining long-run profitability. Perfect competition and monopolistic competition typically yield only normal profits, whereas oligopolies and monopolies can sustain economic profits due to their market power. Understanding these distinctions helps analyze real-world markets and predict firm behavior.