📚 Year 9 WJEC Economics: Unit Test Mock Paper Walkthrough | 9 年级 WJEC 经济单元测试模拟卷解析
This walkthrough provides detailed explanations for a mock unit test designed for Year 9 students following the WJEC Economics curriculum. It covers foundational topics including scarcity, opportunity cost, factors of production, production possibility curves, specialisation, and how markets work through demand, supply, and equilibrium. Each question is broken down with clear reasoning to help you understand exactly how marks are earned and to reinforce key economic concepts.
本解析为一套面向 WJEC 经济学课程的 9 年级单元模拟测试卷提供详细讲解。模拟卷涵盖稀缺性、机会成本、生产要素、生产可能性曲线、专业化以及市场运作（需求、供给与均衡）等基础主题。每道题目都配有清晰的思路分析，帮助你准确理解得分要点，巩固核心经济概念。
1. Exam Structure & Key Themes | 试卷结构与核心主题
The mock paper is divided into three sections: Section A contains ten multiple‑choice questions (10 marks), Section B has two short‑answer questions (10 marks), and Section C features one data‑response question (10 marks). The total time allowed is 45 minutes. The test focuses on Unit 1 themes from the WJEC GCSE Economics specification, specifically the introductory building blocks: the basic economic problem, factors of production, opportunity cost, PPC diagrams, specialisation, and the determination of market prices.
模拟卷分为三个部分：A 部分为 10 道选择题（10 分），B 部分为 2 道简答题（10 分），C 部分为 1 道数据分析题（10 分）。总时间为 45 分钟。试卷围绕 WJEC GCSE 经济学大纲的单元 1 核心主题，重点考查基础模块：基本经济问题、生产要素、机会成本、PPC 图示、专业化以及市场价格的决定。
2. Multiple Choice Q1–3: Scarcity, Choice & Factors | 选择题 Q1–3：稀缺、选择与生产要素
Question 1: What is the fundamental economic problem faced by all societies?
A. How to eliminate inflation
B. How to make unlimited goods with limited labour
C. Unlimited wants and limited resources
D. How to distribute income equally
The correct answer is C. The basic economic problem is scarcity – human wants are unlimited, but the resources (land, labour, capital and enterprise) available to satisfy those wants are finite. This forces every society to make choices about what, how and for whom to produce. Options A, B and D describe policy goals or specific constraints, not the universal economic problem.
第 1 题： 所有社会面临的基本经济问题是什么？
A. 如何消除通货膨胀
B. 如何在劳动力有限的情况下生产无限商品
C. 无限欲望与有限资源
D. 如何平等分配收入
正确答案是 C。基本经济问题是稀缺性——人类的欲望是无限的，而可用于满足这些欲望的资源（土地、劳动力、资本和企业精神）是有限的。这迫使每个社会都必须就生产什么、如何生产和为谁生产做出选择。选项 A、B 和 D 描述的是政策目标或具体约束，并非普遍意义上的经济问题。
Question 2: A factory manager decides to use an extra machine instead of hiring two more workers. The opportunity cost of this decision is the
A. cost of the machine
B. wages of the two workers
C. output produced by the machine
D. output those two workers could have produced
The answer is D. Opportunity cost is the value of the next best alternative forgone. By choosing the machine, the firm gives up the potential output the two workers could have generated. Option B identifies the wage saving, but the real cost is the lost production, not the money saved. A and C focus on benefits of the chosen option, not the forgone alternative.
第 2 题： 一位工厂经理决定多使用一台机器，而不是多雇两名工人。这个决策的机会成本是
A. 机器的成本
B. 两名工人的工资
C. 机器生产的产量
D. 那两名工人本可以生产的产量
答案是 D。机会成本是所放弃的次优选择的价值。在选择机器的同时，企业放弃了那两名工人本可以带来的产量。选项 B 指的是省下的工资，但真正的成本是损失的生产，而非节省的钱。A 和 C 侧重于所选方案的收益，而非被放弃的方案。
Question 3: Which of the following is an example of the factor of production 'capital'?
A. A farmer working in a field
B. An oil deposit under the sea
C. A robot used on an assembly line
D. The willingness to start a new business
The correct choice is C. In economics, capital refers to man‑made goods used in the production of other goods and services, such as machinery, tools and factories. A farmer is labour (A), an oil deposit is land (B), and willingness to start a business is enterprise (D).
第 3 题： 下列哪一项属于生产要素中的“资本”？
A. 在田间劳作的农民
B. 海底的石油矿藏
C. 装配线上使用的机器人
D. 创业的意愿
正确选项为 C。在经济学中，资本指用于生产其他商品和服务的人造物品，如机器、工具和厂房。农民属于劳动力（A），石油矿藏属于土地（B），创业意愿属于企业精神（D）。
3. Multiple Choice Q4–6: PPC, Specialisation & Markets | 选择题 Q4–6：生产可能性曲线、专业化与市场
Question 4: The diagram below shows a production possibility curve (PPC) for an economy producing consumer goods and capital goods. (Assume the curve is bowed outward.) A point inside the PPC indicates
A. an unattainable combination of goods
B. a combination that uses all resources fully and efficiently
C. the maximum possible output of consumer goods
D. that some resources are unemployed or used inefficiently
D is correct. A point inside the frontier means the economy is not using all its resources, or is using them inefficiently, so actual output is below its potential. Points on the curve represent full and efficient utilisation, while points outside are currently unattainable.
第 4 题： 下图显示了一个经济体生产消费品和资本品的生产可能性曲线（PPC）（假设曲线外凸）。位于 PPC 内部的点表示
A. 一种无法实现的商品组合
B. 充分利用所有资源且高效生产的组合
C. 消费品可能的最大产量
D. 部分资源未被利用或利用效率低下
D 正确。位于边界内部的点意味着经济没有充分利用其全部资源，或者利用效率低下，因此实际产出低于潜在产出。位于曲线上的点代表充分且高效利用；位于曲线外的点则是当前无法实现的。
Question 5: Specialisation and the division of labour can increase productivity primarily because
A. workers become bored and change jobs often
B. firms can produce a wider variety of products
C. workers concentrate on one task and become highly skilled in it
D. transport costs are eliminated
The answer is C. Specialisation allows workers to focus on a narrow range of tasks, improving speed, skill and efficiency. While boredom is a potential disadvantage (A), that does not increase productivity. B describes variety of output, not the direct cause of productivity gains. D is unrealistic.
第 5 题： 专业化和劳动分工能够提高生产率，主要原因在于
A. 劳动者感到乏味并频繁更换工作
B. 企业可以生产更多种类的产品
C. 劳动者专注于一项任务并变得高度熟练
D. 运输成本被消除
答案是 C。专业化使工人可以专注于少数任务，从而提高速度、技能和效率。感到乏味是潜在劣势（A），但不会提高生产率。B 描述的是产出种类，并非生产率提升的直接原因。D 不切实际。
Question 6: In a free market economy, what primarily determines the allocation of resources?
A. Government planning committees
B. The price mechanism
C. Tradition and custom
D. Equal shares for all households
B is correct. In a market economy, the interaction of demand and supply determines prices, and these price signals guide producers on what to make, how to produce and for whom. Governments play a smaller role, so A is not the main driver. Tradition (C) applies to traditional economies, and equal shares (D) is a value goal, not a market mechanism.
第 6 题： 在自由市场经济中，资源配置主要由什么决定？
A. 政府计划委员会
B. 价格机制
C. 传统与习俗
D. 所有家庭均等份额
B 正确。在市场经济中，需求与供给的相互作用决定价格，这些价格信号引导生产者决定生产什么、如何生产以及为谁生产。政府作用较小，因此 A 并非主要驱动力。传统（C）适用于传统经济，均等份额（D）是一种价值目标，而非市场机制。
4. Multiple Choice Q7–10: Demand, Supply & Equilibrium | 选择题 Q7–10：需求、供给与均衡
Question 7: If the price of butter rises significantly, the demand for margarine (a close substitute) is likely to
A. decrease because consumers buy less of both
B. increase as consumers switch to the cheaper alternative
C. stay the same because tastes do not change
D. fall because margarine becomes more expensive to produce
B is the answer. Butter and margarine are substitutes. When the price of butter rises, consumers look for cheaper alternatives, so demand for margarine shifts to the right. A suggests they are complements, which is not the case. C ignores the substitution effect. D relates to supply, not demand.
第 7 题： 如果黄油价格大幅上涨，那么人造黄油（一种相近替代品）的需求可能会
A. 减少，因为消费者对二者的购买均减少
B. 增加，因为消费者转向更便宜的替代品
C. 保持不变，因为口味没有变化
D. 下降，因为人造黄油的生产成本变得更高
答案为 B。黄油与人造黄油为替代品。当黄油价格上涨时，消费者会寻找更便宜的替代品，因此人造黄油的需求会向右移动。A 暗示它们是互补品，与事实不符。C 忽略了替代效应。D 涉及供给，而非需求。
Question 8: A government grants a subsidy to producers of solar panels. In the market for solar panels, this will most likely lead to
A. a shift of the supply curve to the left
B. a movement up along the existing supply curve
C. a shift of the supply curve to the right
D. a decrease in the quantity demanded
C is correct. A subsidy lowers production costs, enabling producers to supply more at each price level, so the supply curve shifts right. A leftward shift (A) would be caused by higher costs. A movement along the curve (B) results from a price change, not a subsidy. Quantity demanded will actually increase as price falls, so D is wrong.
第 8 题： 政府向太阳能电池板生产商提供补贴。在太阳能电池板市场中，这最有可能导致
A. 供给曲线向左移动
B. 沿现有供给曲线的向上移动
C. 供给曲线向右移动
D. 需求量减少
C 正确。补贴降低了生产成本，使生产商在每个价格水平上都能提供更多产品，因此供给曲线向右移动。向左移动（A）是由成本上升引起的。沿曲线移动（B）源自价格变动，而非补贴。随着价格下降，需求量实际上会增加，故 D 错误。
Question 9: The table shows the demand and supply schedule for a good at different prices.
| Price (£) | Quantity Demanded | Quantity Supplied |
|---|---|---|
| 10 | 200 | 800 |
| 8 | 300 | 600 |
| 6 | 400 | 400 |
| 4 | 500 | 200 |
| 2 | 600 | 100 |
A. £8
B. £6
C. £4
D. £10
B is the equilibrium price. At £6, quantity demanded (400) equals quantity supplied (400), so the market clears. At £8 and £10 there is excess supply; at £4 and £2 there is excess demand.
第 9 题： 表格显示某商品在不同价格下的需求与供给表。均衡价格是多少？
A. £8
B. £6
C. £4
D. £10
B 是均衡价格。价格为 £6 时，需求量（400）等于供给量（400），市场出清。£8 和 £10 时存在超额供给；£4 和 £2 时存在超额需求。
Question 10: When there is excess supply in a market, we would expect the price to
A. rise until the surplus is eliminated
B. first rise, then fall below equilibrium
C. stay constant because producers will not change prices
D. fall until quantity demanded equals quantity supplied
D is correct. Excess supply (a surplus) puts downward pressure on price. As price falls, quantity demanded rises and quantity supplied contracts, moving the market back to equilibrium. A describes the reaction to excess demand. C ignores market forces.
第 10 题： 当市场存在超额供给时，我们预期价格会
A. 上升，直到剩余消除
B. 先上升，然后降至均衡以下
C. 保持不变，因为生产商不会改变价格
D. 下跌，直到需求量等于供给量
D 正确。超额供给（过剩）会给价格带来下行压力。随着价格下跌，需求量上升，供给量收缩，市场重新回到均衡。A 描述的是对超额需求的反应。C 忽略了市场力量。
5. Short‑answer Q1: Opportunity Cost Calculation | 简答题 1：机会成本计算
Question: A farmer can use a field to grow either wheat or potatoes. The table shows two possible output combinations.
| Combination | Wheat (tonnes) | Potatoes (tonnes) |
|---|---|---|
| A | 100 | 0 |
| B | 70 | 50 |
(b) Explain what this opportunity cost means. (2 marks)
Answer (a): as 100 − 70 = 30 tonnes of wheat. So the opportunity cost is 30 tonnes of wheat. (2 marks)
Answer (b): Opportunity cost represents the value of the next best alternative foregone. In this case, by choosing to produce 50 tonnes of potatoes (moving to B), the farmer sacrifices the ability to produce 30 tonnes of wheat that could have been produced under combination A. Even if no money changes hands, the real cost of the potatoes is the wheat output that society loses. (2 marks)
题目： 一位农民可以用一块地种植小麦或土豆。表格显示了两种可能的产出组合。
| 组合 | 小麦（吨） | 土豆（吨） |
|---|---|---|
| A | 100 | 0 |
| B | 70 | 50 |
(b) 解释这一机会成本的含义。（2 分）
答案 (a)： 获得额外 50 吨土豆的机会成本是必须放弃的 30 吨小麦。计算方式为 100−70=30 吨小麦。因此，机会成本为 30 吨小麦。（2 分）
答案 (b)： 机会成本代表了所放弃的次优选择的价值。在本例中，通过选择生产 50 吨土豆（移向 B），农民牺牲了在组合 A 下本可以生产的 30 吨小麦。即使没有发生金钱交易，土豆的真实成本是社会所损失的小麦产出。（2 分）
6. Short‑answer Q2: Shifts in Demand & Supply | 简答题 2：需求与供给的移动
Question: The government introduces a new regulation requiring all ride‑hailing drivers to undergo an expensive safety certification. Analyse the likely impact on the market for ride‑hailing services. You should refer to both supply and equilibrium price/quantity. (6 marks)
Model answer: The expensive certification raises the cost of providing ride‑hailing services. This is a non‑price determinant of supply, so the supply curve will shift to the left (a decrease in supply). At every price, fewer drivers are willing and able to offer services. With demand unchanged, the leftward shift creates a shortage at the original equilibrium price, putting upward pressure on price. The market will move to a new equilibrium with a higher price and a lower quantity of rides traded. Therefore, consumers face higher fares, and the number of journeys contracts while some drivers leave the market due to higher costs. (Diagram description: supply shifts left, P rises, Q falls.)
题目： 政府出台新规定，要求所有网约车司机参加一项昂贵的安全认证。分析这一规定对网约车服务市场可能产生的影响。请同时提及供给以及均衡价格与数量。（6 分）
标准答案： 昂贵的安全认证提高了提供网约车服务的成本。这是影响供给的非价格决定因素，因此供给曲线将向左移动（供给减少）。在每个价格水平上，愿意且能够提供服务的司机变少。在需求不变的情况下，左移会在原均衡价格处造成短缺，给价格带来上行压力。市场将移向新的均衡：价格更高，成交量更低。因此，消费者面临更高的车费，行程数量缩减，部分司机因成本增加退出市场。（图示描述：供给左移，P 上升，Q 下降。）
7. Data‑response Q3: Interpreting a Market Diagram | 数据分析题 3：解读市场图示
Question: The table below shows the daily demand and supply for bottles of fresh juice in a school canteen.
| Price (£) | Qd (bottles) | Qs (bottles) |
|---|---|---|
| 1.00 | 80 | 20 |
| 1.50 | 60 | 40 |
| 2.00 | 50 | 50 |
| 2.50 | 30 | 60 |
| 3.00 | 20 | 70 |
(b) Suppose a health campaign increases students' preference for juice. At the original equilibrium price, describe the market condition and explain how the new equilibrium is reached. (4 marks)
(c) Calculate the total revenue at the original equilibrium. (2 marks)
(d) After the demand increase, the new equilibrium price is £2.50. By how much has total revenue changed? (2 marks)
Answer (a): Equilibrium occurs where Qd
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