📚 KS3 OCR Economics: Case Study Practical Drills | KS3 OCR 经济：案例分析实战演练
This article takes you through a series of real-world case studies that bring KS3 OCR Economics to life. Each scenario is designed to strengthen your ability to apply core economic ideas – from scarcity and opportunity cost to supply and demand, money, and personal budgeting. Work through the drills, then test your understanding with exam-style questions.
本文将通过一系列真实案例，将 KS3 OCR 经济学的核心概念变得生动具体。从稀缺性与机会成本，到供需关系、货币与个人预算，每个场景都旨在锻炼你运用经济学知识的能力。跟随实战演练，再用考试风格的问题检验自己的理解。
1. Understanding Scarcity: The Birthday Money Dilemma | 理解稀缺性：生日钱的困境
Ben has just turned 13 and received £50 for his birthday. He really wants three things: a new video game costing £30, a cinema ticket with popcorn for £15, and a pizza night with friends for £10. Adding them up comes to £55, but Ben only has £50. He cannot have everything he wants, so he must make a choice.
Ben 刚满13岁，收到了 £50 生日礼金。他非常想要三样东西：价值 £30 的新电子游戏、£15 的电影票加爆米花，以及 £10 的朋友披萨之夜。三项合计 £55，但 Ben 只有 £50。他无法得到所有想要的，因此必须做出选择。
This everyday problem illustrates the fundamental economic problem of scarcity. Resources (Ben’s money) are limited, but his wants are unlimited. Economics studies how people, businesses and governments make choices when faced with scarcity. The three basic economic questions arise: What to produce? How to produce? For whom to produce? In Ben’s world, the question becomes: which good will he choose to ‘produce’ for himself by spending his limited income?
这个日常问题揭示了根本性的经济问题：稀缺性。资源（Ben 的钱）是有限的，而他的欲望是无限的。经济学研究的是个人、企业和政府在面临稀缺时如何做出选择。由此产生三个基本经济问题：生产什么？如何生产？为谁生产？ 在 Ben 的世界中，问题变成了：他要用有限的收入为自己“生产”哪一样物品？
Scarcity forces trade-offs. If Ben picks the game, he must give up the cinema and pizza. Economics helps us weigh up the alternatives and understand the cost of our decisions.
稀缺性迫使人们进行权衡。如果 Ben 选了游戏，他就得放弃电影和披萨。经济学帮助我们衡量各种选项，并理解决策背后的代价。
2. Opportunity Cost in Action: The Choice of a New Phone | 机会成本实战：新手机的选择
Sara has saved £200 from her weekend job. She narrows her desired purchases to two items: a new smartphone priced at exactly £200, and a tablet that costs £250 (she would need to borrow £50 from her parents for the tablet). Her first choice is the phone. The next best alternative she must give up is the tablet. Even though she can’t afford the tablet without borrowing, it remains her second most valued option.
Sara 在周末兼职中攒下了 £200。她将想买的物品缩小到两样：一部正好 £200 的新智能手机，以及一台售价 £250 的平板电脑（买平板需要向父母借 £50）。她的首选是手机。她必须放弃的次优选择就是平板电脑。尽管她需要借钱才能买平板，但它仍然是她第二看重的选项。
The opportunity cost of a choice is the value of the next best alternative forgone. For Sara, the opportunity cost of buying the smartphone is the enjoyment and usefulness she would have gained from the tablet. Notice that opportunity cost is not the money spent; it is the lost benefit of the alternative. Understanding opportunity cost helps us see that every decision has a hidden price tag.
一项选择的机会成本，是被放弃的次优选项的价值。对 Sara 而言，购买智能手机的机会成本是她本可以从平板电脑中获得的乐趣与用途。注意，机会成本不是花掉的钱本身，而是放弃的替代品所带来的效益。理解机会成本能让我们意识到，每个决策都隐藏着代价。
Governments also face opportunity costs. If a council spends £1 million on a new playground, the opportunity cost might be the road repairs they cannot fund. Always ask: ‘What is the next best thing given up?’
政府同样面临机会成本。如果议会花费100万英镑修建新游乐场，其机会成本可能就是无法资助的道路维修。永远要问：“被放弃的次优方案是什么？”
3. Supply and Demand: Running a School Tuck Shop | 供需关系：经营学校小吃店
Imagine you run a tuck shop selling healthy flapjacks at break time. You notice that when the price is high, students buy fewer flapjacks; when the price is low, they buy more. This is the law of demand. At the same time, you are more willing to supply flapjacks at higher prices because you can make greater profit – that is the law of supply.
想象一下，你在课间休息时经营着一家售卖健康燕麦棒的小吃店。你发现价格高时，学生买得少；价格低时，他们会多买。这就是需求定律。与此同时，你更愿意在价格较高时供应更多燕麦棒，因为你可以获得更高利润——这就是供给定律。
Let’s examine a demand and supply schedule:
我们来看看供需计划表：
| Price per flapjack (p) | Quantity demanded (per day) | Quantity supplied (per day) |
|---|---|---|
| 50p | 20 | 100 |
| 40p | 40 | 80 |
| 30p | 60 | 60 |
| 20p | 90 | 40 |
| 10p | 130 | 10 |
The equilibrium price is 30p, where quantity demanded equals quantity supplied (60 flapjacks). If the price were set at 50p, there would be a surplus because supply exceeds demand. At 20p, a shortage would occur as demand outstrips supply. Prices tend to move toward equilibrium naturally.
均衡价格为30便士，此时需求量等于供给量（60根燕麦棒）。若价格定为50便士，会出现过剩，因为供给量大于需求量。若价格定为20便士，会出现短缺，因为需求量超过供给量。价格通常会自然趋向均衡。
4. Market Equilibrium: Concert Ticket Frenzy | 市场均衡：音乐会门票狂潮
A popular band announces a concert with only 300 seats available. The organisers set the ticket price at £50. At that price, 500 fans want to buy tickets. The quantity demanded (500) far exceeds the quantity supplied (300), creating a large shortage. Queues form, and many fans are left disappointed.
某支热门乐队宣布举办演唱会，但仅有300个座位。主办方将票价定为 £50。在此价格下，有500名粉丝想购票。需求量（500）远超供给量（300），造成严重短缺。人们排起长队，许多粉丝失望而归。
Because tickets are scarce, some fans are willing to pay more. A secondary market emerges where tickets resell for £100 or higher. The price rises until the quantity supplied (official tickets plus resold ones) matches the quantity demanded at the higher price. This is the price mechanism allocating scarce resources to those who value them most (and can afford them).
由于门票稀缺，一些粉丝愿意支付更高价格。二级市场随之出现，门票转售价涨至 £100 或更高。价格持续上升，直至供给量（官方票加上转售票）与较高价位下的需求量相等。这就是价格机制在分配稀缺资源，将其引导至最珍视（且有支付能力）的人手中。
If the government imposed a maximum price of £50 to be ‘fair’, the shortage would persist, and many tickets might be allocated by luck rather than willingness to pay. Thinking about shortage and surplus helps us evaluate both market outcomes and interventions.
如果政府为了“公平”设定 £50 的最高限价，短缺将持续，许多门票可能会靠运气而非支付意愿来分配。思考短缺与过剩能帮助我们评价市场结果及干预措施。
5. Specialisation and Trade: The Two Farmers | 专业化与贸易：两个农场主
Farmer A can produce in one day either 10 kg of wheat or 5 kg of beef. Farmer B can produce either 6 kg of wheat or 12 kg of beef. On his own, Farmer A must split his time to get both, and so must Farmer B. However, if Farmer A specialises in wheat and Farmer B specialises in beef, they can trade their surpluses.
农夫 A 每天可以生产 10 公斤小麦或 5 公斤牛肉。农夫 B 每天可以生产 6 公斤小麦或 12 公斤牛肉。若各自单独生产，两人都得分出时间获得两种产品。然而，如果农夫 A 专门生产小麦，农夫 B 专门生产牛肉，他们便可用剩余产品进行交换。
Suppose they agree to trade 6 kg of wheat for 6 kg of beef. After specialisation, Farmer A produces 10 kg wheat, keeps 4 kg and trades 6 kg for 6 kg beef – he ends up with more beef than he could have produced alone. Farmer B produces 12 kg beef, keeps 6 kg and trades 6 kg for 6 kg wheat – she also gains more wheat. Both are better off through specialisation and trade.
假设他们商定用 6 公斤小麦交换 6 公斤牛肉。专业化后，农夫 A 生产 10 公斤小麦，自留 4 公斤，用 6 公斤换回 6 公斤牛肉——最终获得的牛肉比自己生产时更多。农夫 B 生产 12 公斤牛肉，自留 6 公斤，用 6 公斤换 6 公斤小麦——她获得的小麦也增加了。通过专业化与贸易，双方状况都得到了改善。
This simple case shows how absolute advantage (Farmer A in wheat, Farmer B in beef) leads to gains from trade. On a larger scale, countries specialise in goods they can produce relatively efficiently and trade with others, raising overall living standards.
这个简单例子展示了绝对优势（农夫 A 在小麦上，农夫 B 在牛肉上）如何带来贸易收益。在更大层面上，各国会专门生产自己相对高效的产品，并与他国交易，从而提升整体生活水平。
6. The Functions of Money: From Barter to Banknotes | 货币的职能：从物物交换到纸币
Before money existed, people relied on barter – swapping one good directly for another. Imagine a baker who wants some milk. He must find a dairy farmer who happens to want bread at the same time. This is called a double coincidence of wants, and it is rare and inefficient. The baker might have to trade bread for eggs first, then eggs for milk, wasting time and resources.
在货币出现之前，人们依赖物物交换——直接以一种物品换取另一种。想象一位面包师想获得一些牛奶。他必须找到一个恰好同时想要面包的奶农。这被称为需求的双重巧合，这种情况既罕见又低效。面包师可能得先用面包换鸡蛋，再用鸡蛋换牛奶，浪费了大量时间和资源。
Money solves this problem by serving three essential functions: a medium of exchange (everyone accepts it), a unit of account (prices can be compared easily), and a store of value (you can save it for future use). With pounds sterling, the baker simply sells bread for money and uses that money to buy milk whenever he needs it.
货币解决了这个问题，它发挥着三项基本职能：交换媒介（人人都接受）、计价单位（便于比较价格）以及价值储藏（可储存供未来使用）。有了英镑，面包师只需把面包卖了换钱，再用钱随时购买牛奶即可。
Modern money includes coins, notes and digital bank balances. The central bank controls the supply of money to keep its value stable. Without money’s functions, the economy would slow to a crawl.
现代货币包括硬币、纸币和数字银行存款。中央银行调控货币供给以稳定其价值。若没有货币的这些职能，经济将几乎停摆。
7. Public Goods and Government: Who Pays for the Streetlights? | 公共物品与政府：谁来支付路灯？
A streetlight provides lighting for everyone on the road – you cannot exclude someone from benefiting, even if they haven’t paid for it. This is called non-excludability. Furthermore, one person enjoying the light does not reduce the light available to others – this is non-rivalry. Goods that are both non-excludable and non-rival are called public goods.
路灯为路上的每个人提供照明——你无法阻止未付费的人享受灯光，这被称为非排他性。此外，一个人享受灯光并不会减少他人获得的照明，这被称为非竞争性。同时具备非排他性和非竞争性的物品被称为公共物品。
Streetlights, lighthouses, flood defences and national defence are all public goods. Private firms have little incentive to provide them because they cannot easily charge every user. This is a classic market failure. Therefore, the government steps in to fund public goods through taxation, ensuring they are available for all.
路灯、灯塔、防洪设施和国防都属于公共物品。私营企业几乎没有动力提供它们，因为很难向每位使用者收费。这是典型的市场失灵。因此，政府通过税收来资助公共物品，确保人人皆可享用。
When you pay council tax, part of it pays for street lighting and local parks. Understanding public goods helps explain why some things are best provided collectively rather than by free markets.
当你缴纳市政税时，其中一部分便用于支付路灯和本地公园。理解公共物品有助于解释为何某些东西最好由集体提供，而非依赖自由市场。
8. Personal Budgeting: Saving for a Dream Holiday | 个人预算：为梦想假期储蓄
Jamie receives £25 pocket money per month and wants to go on a school ski trip costing £300 in eight months’ time. With a simple budget, Jamie calculates that by saving £25 each month, she would only reach £200 by the deadline. She must either increase income, reduce other spending, or a mix of both.
Jamie 每月有 £25 零花钱，她希望参加八个月后费用为 £300 的学校滑雪旅行。通过简单预算，Jamie 算出如果每月存 £25，到截止日仅能攒到 £200。她必须增加收入、减少其他开支，或双管齐下。
Jamie decides to do extra chores for £10 per month, boosting her monthly income to £35. She also cuts back on snacks, saving an additional £5. Now she can save £40 per month. Over eight months that’s £320 – enough for the trip and a small emergency buffer. This is budgeting: planning income and expenditure to meet financial goals.
Jamie 决定每月额外做家务挣 £10，使月收入增至 £35。她还减少了零食开销，多省下 £5。现在她每月能存 £40。八个月就是 £320——足够支付旅行，还有一点应急缓冲。这就是预算：规划收支以实现财务目标。
A personal budget shows fixed expenses (like phone top-up) and discretionary spending. By distinguishing needs from wants, you can make smarter financial decisions. Setting a savings goal also teaches the discipline of deferred gratification.
个人预算会列出固定支出（如手机充值）和可自由支配的开销。区分需要与想要，有助于做出更明智的财务决策。设定储蓄目标还能培养延迟满足的自律能力。
9. Interpreting Economic Data: Reading Graphs and Tables | 解读经济数据：阅读图表
KS3 OCR Economics often asks you to interpret data. For example, a graph might show market demand shifting to the right due to a new health campaign that makes flapjacks more popular. At every price, quantity demanded rises. This shift is different from a movement along the demand curve caused by a price change.
KS3 OCR 经济学常常要求你解读数据。例如，某图表可能显示由于一项新的健康宣传活动提高了燕麦棒的人气，市场需求曲线向右移动。在每一价格下，需求量都上升了。这种移动不同于因价格变化引起的沿需求曲线的移动。
Look at the table below for the tuck shop after a ‘healthy eating’ campaign:
请查看健康饮食宣传活动后小吃店的数据表：
| Price (p) | Original Qd | New Qd after campaign |
|---|---|---|
| 50p | 20 | 40 |
| 40p | 40 | 65 |
| 30p | 60 | 90 |
| 20p | 90 | 130 |
The entire demand curve has shifted rightward. At the old equilibrium price of 30p, the new quantity demanded is 90, far exceeding the supplied 60. A shortage of 30 flapjacks now exists. The market price will likely rise to a new equilibrium where supply equals the higher demand.
整条需求曲线向右移动了。在原来30便士的均衡价格下，新的需求量高达90，远超供应量60。现在出现了30根燕麦棒的短缺。市场价格很可能会上涨到新的均衡点，使供给与更高的需求匹配。
When answering questions, identify shift factors (e.g. taste, income, advertising) versus price changes. Use clear labels on diagrams and refer to data in your explanations.
答题时，要识别变动因素（如偏好、收入、广告）与价格变动的区别。在图表上清晰标注，并在解释中引用数据。
10. Exam-Style Case Study Questions and Model Answers | 考试风格案例分析问答与范例答案
Case Study: A local council is considering whether to build a new sports centre (£800,000) or repair three playgrounds (£200,000 each). Its budget is £800,000.
案例：某地方议会正在考虑是修建一座新体育中心（花费 £800,000），还是修缮三个游乐场（每个需 £200,000）。其预算为 £800,000。
Question 1: Define opportunity cost. (1 mark)
问题1：定义机会成本。（1分）
Model answer: Opportunity cost is the value of the next best alternative given up when a choice is made.
范例答案：机会成本是在做出选择时所放弃的次优选项的价值。
Question 2: What is the opportunity cost for the council if it chooses the sports centre? (2 marks)
问题2：若议会选择体育中心，其机会成本是什么？（2分）
Model answer: The opportunity cost is the three repaired playgrounds (or the benefit children would get from those playgrounds). The next best alternative is completely forgone, so the council loses the safety and enjoyment the playgrounds would provide.
范例答案：机会成本是三个得到修缮的游乐场（或者说儿童从这些游乐场中获得的益处）。次优选项被完全放弃，因此议会失去了游乐场原本能提供的安全与快乐。
Question 3: Explain how the concept of scarcity applies to this decision. (3 marks)
问题3：解释稀缺性概念如何适用于这项决策。（3分）
Model answer: Scarcity means that the council’s financial resources are limited while the community’s wants are unlimited. The £800,000 budget is not enough to fund both the sports centre and the playground repairs. Therefore, the council must prioritise and make a choice, illustrating the basic economic problem.
范例答案：稀缺性意味着议会的财政资源有限，而社区的欲望无限。£800,000 的预算不足以同时资助体育中心和游乐场修缮。因此，议会必须优先排序并做出选择，这体现了基本经济问题。
Question 4: Suggest and explain one non-financial factor the council might consider. (2 marks)
问题4：建议并解释议会可能会考虑的一个非财务因素。（2分）
Model answer: The council might consider the health benefits to residents. A sports centre could reduce obesity and improve mental wellbeing across all age groups, which creates long-term social value that isn’t captured in the immediate price tag.
范例答案：议会可能会考虑居民的健康效益。体育中心有助于减少肥胖、改善所有年龄段人群的心理健康，从而创造长远的社会价值，这种价值并未包含在直接的价目表中。
Practise writing concise yet fully reasoned answers. Keep linking back to economic terms: scarcity, choice, opportunity cost, trade-off, and public goods where relevant.
练习写作简洁且论证充分的答案。始终回扣经济术语：稀缺性、选择、机会成本、权衡，以及相关的公共物品等。
Published by TutorHao | Economics Revision Series | aleveler.com
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