Year 7 WJEC Economics: Case Study in Action | Year 7 WJEC 经济：案例分析实战演练

📚 Year 7 WJEC Economics: Case Study in Action | Year 7 WJEC 经济：案例分析实战演练

Ready to see how the basic ideas of economics come alive in the real world? In this practical drill, we will follow Lily, a Year 7 student with a dream of running a lemonade stand. Her story will help us explore scarcity, choice, opportunity cost, demand and supply, and much more in a hands‑on way. By the end, you will have the confidence to tackle your own case study like a true economist. | 准备好看看经济学的基本概念是如何在现实中生动体现的吗？在这次实战演练中，我们将跟随莉莉——一名想开柠檬水摊的七年级学生。她的故事将帮助我们亲手探索稀缺性、选择、机会成本、需求与供给等诸多内容。到最后，你将有信心像一位真正的经济学家一样处理自己的案例分析。

Economics is not just about graphs and money; it is about how people make decisions when they cannot have everything they want. Lily’s lemonade stand shows how every choice involves a trade‑off, and how small business decisions connect to larger economic principles. Let us dive into her summer project and learn by doing. | 经济学不仅仅是图表和金钱；它是关于人们在无法拥有一切时如何做决定。莉莉的柠檬水摊展示了每一个选择都涉及权衡取舍，以及小小的商业决策如何与更大的经济原理联系起来。让我们一起深入研究她的暑假计划，边做边学。

1. Introducing the Case: Lily’s Lemonade Stand | 案例引入：莉莉的柠檬水摊

Lily loves making lemonade for her family. This summer, she decides to set up a stall in her front garden. Her goal is to earn some pocket money, but she quickly realises that she faces a big problem: her resources are limited. She has saved up exactly £10 from her birthday money to spend on everything she needs. | 莉莉喜欢为家人制作柠檬水。今年夏天，她决定在自家前花园摆一个摊。她的目标是赚取一些零花钱，但她很快意识到她面临一个大问题：她的资源是有限的。她生日时攒下的钱刚好有10英镑，要用来购买所需的一切。

She also has a time limit – only one weekend to run the stand – and she has to use her mum’s kitchen equipment. Right away, Lily is dealing with the fundamental economic problem of scarcity: her wants (lots of materials and time) are greater than the resources available. What will she do? | 她还有时间限制——只有周末两天可以摆摊——而且她只能使用妈妈的厨房设备。莉莉立刻就遇到了基本的经济问题——稀缺性：她的欲望（想要很多材料和大量时间）超过了可用的资源。她会怎么做？

2. Scarcity and Choice: Limited Resources Force Decisions | 稀缺性与选择：有限资源迫使做出决定

Because Lily cannot buy unlimited ingredients, she must make choices. Scarcity means that resources such as money, time and raw materials are finite, so people have to decide how to use them. In our case, the £10 cash is a scarce resource. Lily cannot afford to buy every possible item; she needs to pick the combination that will help her make the most lemonade. | 由于莉莉无法无限购买配料，她必须做出选择。稀缺性意味着金钱、时间和原材料等资源是有限的，因此人们必须决定如何使用它们。在我们的案例中，10英镑现金就是一种稀缺资源。莉莉无力购买所有可能的物品；她需要挑选能帮助她制作最多柠檬水的组合。

She lists the prices: a bag of lemons costs £2, a bag of sugar costs £1, and cups cost £0.50 each. She also needs water and ice, but water is free from the tap and ice can be made at home. This list helps her see her budget constraint. She must choose how many bags of lemons and sugar to buy without exceeding £10. | 她列出了价格：一袋柠檬2英镑，一袋糖1英镑，杯子每个0.50英镑。她还需要水和冰块，但水可以从水龙头免费获得，冰块可以在家制作。这份清单帮助她看清自己的预算约束。她必须选择买多少袋柠檬和糖，还不能超过10英镑。

English: With £10, Lily could buy 5 bags of lemons and zero sugar, or 10 bags of sugar and zero lemons, but neither extreme makes a proper drink. She must combine them wisely.
中文：用10英镑，莉莉可以买5袋柠檬和零袋糖，或者10袋糖和零袋柠檬，但这两种极端做法都做不出像样的饮料。她必须明智地组合它们。
English: Every choice has a cost: if she buys one more bag of lemons, she has less money for sugar or cups. This is the opportunity cost, which we will examine next.
中文：每个选择都有代价：如果她多买一袋柠檬，她用来买糖或杯子的钱就少了。这就是机会成本，我们接下来会细看。

3. Opportunity Cost: The Next Best Alternative Given Up | 机会成本：放弃的次优选择

In economics, opportunity cost is the value of the next best alternative you give up when you make a decision. For Lily, every spending choice has an opportunity cost. Suppose she decides to buy 3 bags of lemons (£6) and 2 bags of sugar (£2). That uses £8, leaving £2 for 4 paper cups. The next best alternative might be to buy 2 bags of lemons and 4 bags of sugar, which also costs £6+£4=£10, leaving no money for cups at all. | 在经济学中，机会成本是你做决定时放弃的次优选择的价值。对莉莉来说，每一次消费选择都有机会成本。假设她决定买3袋柠檬（6英镑）和2袋糖（2英镑）。这花了8英镑，剩下2英镑买4个纸杯。次优选择可能是买2袋柠檬和4袋糖，这也要花6英镑+4英镑=10英镑，一分钱都不剩来买杯子。

By picking the first combination, she gives up the chance to have more sugar and a different recipe. The opportunity cost of choosing 3 lemons + 2 sugar is the extra sugar she could have had (and the tastier lemonade perhaps). Lily must weigh these trade‑offs carefully. | 通过选择第一种组合，她放弃了拥有更多糖和另一种配方的机会。选择3袋柠檬+2袋糖的机会成本，就是她本可以多拥有的糖（以及可能更好喝的柠檬水）。莉莉必须仔细权衡这些取舍。

Opportunity cost even applies to her time: she could spend the weekend studying or playing video games. By running the stand, the opportunity cost is the enjoyment she foregoes from those activities. Thinking like an economist means always asking: “What am I giving up?” | 机会成本甚至适用于她的时间：她完全可以用周末学习或玩电子游戏。经营柠檬水摊的机会成本，就是她从那些活动中放弃的享受。像经济学家一样思考，就意味着要常问：“我放弃了什么？”

4. Factors of Production: What Lily Needs to Produce Lemonade | 生产要素：莉莉生产柠檬水需要什么

To make lemonade, Lily combines factors of production. Economists group them into four categories: land, labour, capital and enterprise. Let us identify each one in Lily’s small business. | 为了制作柠檬水，莉莉需要组合生产要素。经济学家将它们分为四类：土地、劳动、资本和企业家才能。我们来识别莉莉小生意中的每一种要素。

English: Land – includes all natural resources. For Lily, water is a key natural resource, as well as the space in her garden where she sets up the stall. Lemons and sugar also come from the land, but she buys them as raw materials.
中文：土地——包括所有自然资源。对莉莉来说，水是一种关键的自然资源，她摆放摊位的花园空间也是。柠檬和糖也来自土地，但她是作为原材料购买的。
English: Labour – the human effort used in production. Lily will squeeze lemons, stir and serve customers herself. If she asks her younger brother to help, his help is labour too.
中文：劳动——生产中投入的人力。莉莉将自己动手挤柠檬、搅拌和招待顾客。如果她请弟弟帮忙，弟弟的帮助也属于劳动。
English: Capital – man‑made goods used to produce other goods. Her mother’s juicer, a mixing bowl, a ladle and the table for the stall are all capital. The initial £10 itself can be seen as financial capital.
中文：资本——用于生产其他商品的人造物品。她妈妈的榨汁机、搅拌碗、长柄勺和摆摊的桌子都是资本。最初的10英镑本身可以视为金融资本。
English: Enterprise – the person who brings the other three factors together and takes the risk. That is Lily! She has the idea, organises resources and bears the risk of not selling enough cups.
中文：企业家才能——将其他三种要素组合起来并承担风险的人。这就是莉莉！她出主意、组织资源，并承担卖不够杯数的风险。

Even a simple lemonade stand uses all four factors. Recognising them helps Lily understand what she really needs to pay for and what she already has for free. | 即使是一个简单的柠檬水摊也用到了全部四种要素。认清这些要素能帮助莉莉明白她真正需要付钱买的是什么，以及哪些是她已经免费拥有的。

5. Demand and Supply: How Many Cups and at What Price? | 需求与供给：多少人买，定什么价？

Now Lily has her ingredients and a recipe: each bag of lemons and 2 bags of sugar can make about 10 cups of lemonade. With 3 bags of lemons and 2 bags of sugar, she can produce up to 30 cups. But how many cups will customers want to buy? The answer depends on the price. | 现在莉莉有了原料和配方：每袋柠檬配2袋糖大约可以制作10杯柠檬水。按照3袋柠檬和2袋糖，她最多能生产30杯。但是顾客会想买多少杯呢？答案取决于价格。

Demand is the amount of a product that consumers are willing and able to buy at different prices. Lily does a quick survey among her neighbours and finds:

At £1 per cup, about 8 cups would be bought.
At 50p per cup, about 20 cups would be bought.
At 30p per cup, almost 30 cups would be bought.

This is a typical law of demand: as price falls, quantity demanded rises, other things being equal. | 需求是指消费者在不同价格下愿意并且能够购买的产品数量。莉莉在邻居中做了一次快速调查，发现：每杯1英镑时，大约会买8杯；每杯50便士时，大约会买20杯；每杯30便士时，差不多会买30杯。这就是典型的需求定律：其他条件不变，价格下降时需求量上升。

Supply is how much Lily is willing to sell at each price. She is willing to supply more if the price is higher because she could earn more profit. Her supply schedule might be:

At 30p per cup, she would rather sell only 10 cups (it does not feel worth the effort).
At 50p, she is happy to supply up to 25 cups.
At £1, she will try to sell all 30 cups.

This reflects the law of supply: as price rises, quantity supplied rises. | 供给是莉莉在每个价格下愿意出售的数量。她当然愿意在价格更高时多供应，因为她可以赚更多利润。她的供给计划可能是：每杯30便士时她只愿意卖10杯（感觉不值得费事）；每杯50便士时她乐意供应最多25杯；每杯1英镑时她会尽力卖掉全部30杯。这反映了供给定律：价格上升，供给量上升。

6. Market Equilibrium: Where Plans of Buyers and Sellers Match | 市场均衡：买家和卖家计划吻合之处

Let us put Lily’s demand and supply schedules in a table to find the market equilibrium – the price where quantity demanded equals quantity supplied. | 让我们把莉莉的需求和供给计划放进一张表格，来找到市场均衡——即需求量等于供给量时的价格。

Price per Cup	Qty Demanded	Qty Supplied
£1.00	8	30
50p	20	25
30p	30	10

At £1, there would be a surplus: Lily wants to sell 30 cups but customers want only 8. She would have unsold lemonade. At 30p, there is a shortage: 30 demanded but only 10 supplied – customers would leave unhappy. The equilibrium price is somewhere between 50p and £1. If Lily sets the price at 50p, quantity demanded (20) is close to what she is willing to supply (25), and she can adjust to match exactly. For simplicity, assume she sells 22 cups at 50p, achieving equilibrium. | 在1英镑时会出现过剩：莉莉想卖30杯但顾客只想要8杯。她会剩下卖不掉的柠檬水。在30便士时则出现短缺：需求量30但供给只有10——顾客会失望离开。均衡价格在50便士到1英镑之间。如果莉莉定价50便士，需求量（20杯）接近她愿意供应的（25杯），她可以稍作调整以达到均衡。简单起见，假设她在50便士时卖掉22杯，达到市场出清。

Understanding equilibrium helps Lily avoid waste and make customers happy. In a real market, prices are often discovered by trial and error, just like Lily adjusting her stand sign. | 理解均衡有助于莉莉避免浪费，并使顾客满意。在真实市场中，价格往往通过反复尝试被发现，就像莉莉调整她摊位上的标牌一样。

7. Costs, Revenue and Profit: Did Lily Make Money? | 成本、收入与利润：莉莉赚钱了吗？

Economists think in terms of costs, revenue and profit. Lily’s total cost is what she spends on ingredients and cups. With 3 bags of lemons (£6), 2 bags of sugar (£2) and 22 cups at 50p each (£11? Wait, she only had £10, so she could buy 22 cups if each costs £0.50, she would need £11 total. She needs to adjust. Let us recalculate carefully to stay within budget. | 经济学家用成本、收入和利润来思考。莉莉的总成本是她花在原料和杯子上的钱。如果买3袋柠檬（6英镑）、2袋糖（2英镑）和22个杯子（每个0.50英镑为11英镑），总成本为19英镑？不对，她要控制在10英镑以内。我们来仔细重算一下，确保不超预算。

Let us set a realistic plan: Lily buys 2 bags of lemons (£4), 3 bags of sugar (£3) and uses the remaining £3 to buy 6 paper cups? But she wants to sell many cups. So perhaps she buys 2 bags of lemons (£4), 2 bags of sugar (£2) and with the remaining £4 she can buy 8 cups. Then she can make 20 cups of lemonade (each bag of lemons with 1 bag of sugar makes 10 cups). Now she has 8 cups, so she can only serve 8 cups, wasting 12 cups worth of raw materials. That is poor planning. Lily needs to match cups to production. | 让我们制定一个现实的计划：莉莉买2袋柠檬（4英镑）、2袋糖（2英镑），用剩下的4英镑买8个杯子。那么她能生产20杯柠檬水（每袋柠檬配1袋糖出10杯），但只有8个杯子，只能卖8杯，剩下12杯量的原料就浪费了。这计划不周。莉莉需要让杯子数量与产量匹配。

A smarter combination: 2 bags of lemons (£4), 2 bags of sugar (£2) and 8 cups (£4). Total £10. Production is 20 cups, but only 8 cups can be sold. To sell all 20 cups, she needs 20 cups (£10) which would blow the budget if she still buys ingredients. She could reduce the scale: 1 bag lemons (£2), 1 bag sugar (£1), 10 cups (£5) = £8, leaving £2 for decoration or saved. This produces 10 cups exactly. So for this case, assume Lily chooses this prudent plan: cost = £8 for 10 cups. | 一个更聪明的搭配：1袋柠檬（2英镑）、1袋糖（1英镑）、10个杯子（5英镑），总成本8英镑，剩余2英镑可以买装饰或存起来。这正好生产10杯。因此在此案例中，假设莉莉选择这个谨慎的计划：10杯柠檬水的总成本为8英镑。

If she sells all 10 cups at 50p each, her total revenue is 10 × £0.50 = £5. Her profit (or loss) is:

Profit = Total Revenue − Total Cost = £5 − £8 = −£3

Oh no! She made a loss. She needs to either increase the selling price or cut costs. This teaches a vital lesson: a business must cover its costs to survive. | 哦不！她亏损了。她需要要么提高售价，要么降低成本。这教给我们重要的一课：企业必须覆盖成本才能生存。

If Lily charges 80p per cup and sells all 10, revenue = £8, profit = £0 (break‑even). If she charges £1, revenue = £10, profit = £2. Price matters! | 如果莉莉每杯定价80便士且全部卖掉，收入为8英镑，利润为零（保本）。如果定价1英镑，收入10英镑，利润2英镑。价格很关键！

8. Specialisation and Trade: Could Lily Delegate Tasks? | 专业化与贸易：莉莉能分派任务吗？

As Lily gets busier, she thinks about specialisation. Specialisation happens when people focus on the task they do best. Lily is great at squeezing lemons and chatting with customers. Her friend Tom is brilliant at making signs and handling money. If they work together, they can produce more efficiently. | 随着莉莉越来越忙，她想到了专业化。专业化发生在人们专注于自己最擅长的工作时。莉莉擅长挤柠檬和与顾客聊天。她的朋友汤姆擅长制作招牌和管钱。如果他们合作，生产效率会更高。

Lily specialises in production, Tom specialises in sales. They trade their skills: Lily gives Tom free lemonade in return for his help. Both are better off. This simple division of labour increases total output and is a fundamental reason why economies grow. | 莉莉专门负责生产，汤姆专门负责销售。他们交换技能：莉莉给汤姆免费柠檬水换取他的帮助。两人都从中受益。这种简单的劳动分工增加了总产出，也是经济增长的基本原因。

The concept of trade also applies to money: Lily’s customers trade money for lemonade. Both sides gain – customers enjoy a drink, Lily earns revenue. Voluntary exchange creates value. | 贸易的概念也适用于货币：莉莉的顾客用钱交换柠檬水。双方都获益——顾客享受了饮料，莉莉获得了收入。自愿交换创造价值。

9. Economic Decision‑Making: Incentives and Marginal Thinking | 经济决策：激励与边际思维

Economists assume people respond to incentives. Lily is incentivised to work harder if the weather is sunny because more people walk by. If it rains, her incentive to open the stand drops because expected sales fall. | 经济学家假设人们会对激励做出反应。如果天气晴朗，莉莉会受到激励更努力工作，因为路过的人更多。如果下雨，她开摊的激励就下降了，因为预期销量会减少。

Lily also learns to think at the margin. If she has already made 5 cups and wonders whether to make a sixth, she compares the extra (marginal) cost of one more cup with the extra (marginal) revenue. The marginal cost of one more cup is just the extra ingredients and a cup – about 30p. If she can sell it for 50p, the marginal revenue is 50p, so the marginal benefit exceeds marginal cost, and she should make it. This is marginal analysis. | 莉莉还学会了用边际思维。如果她已经做了5杯，在考虑是否做第6杯时，她会比较再多做一杯的额外（边际）成本和额外（边际）收入。多做一杯的边际成本只是更多的原料和一个杯子——大约30便士。如果她能以50便士卖掉，边际收入就是50便士，因此边际收益大于边际成本，她就应该做这第六杯。这就是边际分析。

Understanding incentives and marginal choices helps Lily maximise her profit while avoiding overproduction. | 理解激励和边际选择有助于莉莉最大化利润，同时避免过度生产。

10. Practical Exercise: Build Your Own Lemonade Stand Case | 实战练习：构建你自己的柠檬水摊案例

Now it is your turn to be the economist! Create a new case based on Lily’s experience but change some numbers. Imagine you have £15, lemons cost £3 per bag, sugar £1.50 per bag, and cups £0.80 each. You can make 8 cups from one bag of lemons and one bag of sugar. Decide how many bags to buy and how many cups you need. Then answer: | 现在轮到你当经济学家了！根据莉莉的经历创建一个新案例，但改动一些数字。假设你有15英镑，柠檬每袋3英镑，糖每袋1.50英镑，杯子每个0.80英镑。一袋柠檬加一袋糖可以制作8杯柠檬水。决定你要买多少袋以及需要多少杯子。然后回答：

English: What is your budget constraint?
中文：你的预算约束是什么？
English: What is the opportunity cost if you choose to buy 2 bags of lemons and 2 bags of sugar?
中文：如果你选择买2袋柠檬和2袋糖，机会成本是什么？
English: If you price each cup at £1 and sell all you produce, what is your total revenue, total cost and profit?
中文：如果每杯定价1英镑且全部卖出，你的总收入、总成本和利润各是多少？
English: How would a hot day shift the demand for your lemonade? Draw a rough demand schedule.
中文：大热天会如何改变你的柠檬水需求？画一个粗略的需求计划。

Write down your answers and discuss them with a study partner. Seeing economics in a simple stand helps you master the same logic used in whole countries. | 写下你的答案，并和同学讨论。通过一个简单的小摊理解经济学，有助于你掌握适用于整个国家的相同逻辑。

Published by TutorHao | Economics Revision Series | aleveler.com

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Year 7 WJEC Economics: Case Study in Action | Year 7 WJEC 经济：案例分析实战演练