📚 Year 12 WJEC Economics: Key Terms & Vocabulary Memorisation Guide | Year 12 WJEC 经济：词汇术语速记指南
Economics can feel like a foreign language, but every term is a building block for stronger essays and clearer analysis. This guide breaks down the essential WJEC Year 12 vocabulary into memorable chunks, pairing each concept with a simple memory trick.
经济学有时感觉像一门外语，但每个术语都是构建更有说服力的论文和更清晰分析的基石。本指南将 WJEC Year 12 必备词汇拆解为易于记忆的模块，并为每个概念配上简洁的记忆技巧。
1. The Economic Problem: Scarcity, Choice and Opportunity Cost | 经济问题：稀缺、选择与机会成本
Scarcity is the fundamental condition that exists because society has limited productive resources but unlimited wants. It forces every economy to answer three questions: what to produce, how to produce, and for whom to produce.
稀缺性是由于社会的生产资源有限而欲望无限所导致的基本状况。它迫使每个经济体回答三个问题：生产什么、如何生产以及为谁生产。
Memory aid: think of the word SCARCE as an acronym – Society Cannot Afford Resources to Cover Everything. When you see scarcity, immediately link it to choice and opportunity cost.
记忆辅助：把 SCARCE 当成一个缩略词——Society Cannot Afford Resources to Cover Everything（社会无法负担覆盖一切的资源）。每当看到稀缺性，立刻将其与选择和机会成本联系起来。
An economic good is a product that uses up scarce resources and therefore has an opportunity cost. A free good, such as air, is abundant and has zero opportunity cost.
经济物品会耗费稀缺资源，因此有机会成本。像空气这样的免费物品是充裕的，机会成本为零。
Quick recall: Economic goods have a price; free goods are gifts of nature. In exams, always treat 'free good' as something without any sacrifice of alternatives.
快速回忆：经济物品有价格；免费物品是自然的馈赠。考试中，始终将“免费物品”视为无需牺牲任何替代选择的东西。
The factors of production are the inputs used to create goods and services: land, labour, capital and enterprise. Memorise them as the CELL of the economy – Capital, Enterprise, Land, Labour.
生产要素是用于创造商品与服务的投入：土地、劳动、资本和企业。请将它们记作经济的“CELL”（细胞）——Capital（资本）、Enterprise（企业家才能）、Land（土地）、Labour（劳动）。
Opportunity cost is the value of the next best alternative forgone whenever a choice is made. Not simply 'everything given up' – only the single best other option counts.
机会成本是每次做出选择时所放弃的次优替代选项的价值。不是“放弃的一切”，只有那一个最佳的其它选项才算。
Memory trick: Say it out loud as "Oh! I see what I sacrificed" – Opportunity Cost = the One Choice you let go.
记忆窍门：出声念“Oh! I see what I sacrificed”（哦！我明白我牺牲了什么）——机会成本就是你松手的那个选择。
2. Demand and Supply: The Market Mechanism | 需求与供给：市场机制
The law of demand states that, ceteris paribus, as the price of a good rises, the quantity demanded falls. This inverse relationship gives the demand curve its downward slope.
需求定律指出，在其它条件不变的情况下，商品价格上升，需求量就会下降。这种反向关系使需求曲线向下倾斜。
To recall what shifts the demand curve, use PASIFIC: Population, Advertising, Substitutes (price of), Income (disposable), Fashion/tastes, Interest rates, Complements (price of). These are non-price determinants that shift the whole curve.
要记住哪些因素会使需求曲线移动，使用 PASIFIC：Population（人口）、Advertising（广告）、Substitutes price（替代品价格）、Income（可支配收入）、Fashion/tastes（时尚/偏好）、Interest rates（利率）、Complements price（互补品价格）。这些都是非价格决定因素，能整体移动需求曲线。
The law of supply shows that, ceteris paribus, a higher price leads to a higher quantity supplied. The supply curve slopes upward because producers are willing to offer more when the price covers rising marginal costs.
供给定律表明，在其它条件不变时，价格越高，供给量越大。供给曲线向上倾斜，因为当价格足以覆盖上升的边际成本时，生产者愿意提供更多产品。
Shifts in supply are caused by changes in costs of production or productivity. Memorise the shifters with PINTS WC: Productivity, Indirect taxes, Number of firms, Technology, Subsidies, Weather, Costs of raw materials.
供给曲线的移动由生产成本或生产率的变化引起。用 PINTS WC 记住这些移动因素：Productivity（生产率）、Indirect taxes（间接税）、Number of firms（企业数量）、Technology（技术）、Subsidies（补贴）、Weather（天气）、Costs of raw materials（原材料成本）。
Market equilibrium is where demand equals supply, setting the market-clearing price. A shortage (excess demand) pushes price up; a surplus (excess supply) pushes price down. Think of the 'invisible hand' guiding price back to balance.
市场均衡出现在需求等于供给之处，即市场出清价格。短缺（超额需求）会推高价格；过剩（超额供给）会压低价格。想象“看不见的手”引导价格回归平衡。
3. Elasticity: Measuring Responsiveness | 弹性：反应程度测量
easures the responsiveness of quantity demanded to a change in price. The formula is PED = %ΔQd ÷ %ΔP, and the coefficient is always treated as an absolute value.
价格需求弹性 (PED) 衡量需求量对价格变化的反应程度。公式为 PED = %ΔQd ÷ %ΔP，弹性系数始终取绝对值处理。
Use SPLAT to recall the determinants of PED: Substitutes (number and closeness), Proportion of income spent on the good, Luxury vs necessity, Addictive or habit-forming nature, Time period.
用 SPLAT 记忆 PED 的决定因素：Substitutes（替代品的数量和接近程度）、Proportion of income（占收入的比例）、Luxury vs necessity（奢侈品还是必需品）、Addictive（是否上瘾或形成习惯）、Time period（时间长短）。
Income elasticity of demand (YED) = %ΔQd ÷ % ates an inferior good. Luxury goods have YED > 1, meaning demand grows faster than income.
收入需求弹性 (YED) = %ΔQd ÷ %ΔY。正的 YED 表示正常品；负的 YED 表示劣等品。奢侈品的 YED 大于 1，说明其需求增长快于收入增长。
Cross-price elasticity of demand (XED) = %ΔQd of good A ÷ % B. A positive XED means the goods are substitutes; a negative XED identifies complements.
交叉价格需求弹性 (XED) = A 商品需求量的变动百分比 ÷ B 商品价格的变动百分比。正值表示替代品，负值表示互补品。
Price elasticity of supply (PES) = %ΔQs ÷ %ΔP. The key influences are TSS: Time period, Spare production capacity, and Stocks of finished goods. In the long run, supply is always more elastic because firms can adjust all inputs.
价格供给弹性 (PES) = %ΔQs ÷ %ΔP。主要影响因素是 TSS：Time period（时间长度）、Spare capacity（闲置产能）和 Stocks（制成品库存）。长期中供给总是更有弹性，因为企业可以调整所有投入。
4. Market Efficiency: Consumer and Producer Surplus | 市场效率：消费者与生产者剩余
Consumer surplus is the extra benefit consumers receive when they pay a price lower than the maximum they are willing to pay. Producer surplus is the extra benefit producers get when they sell above their minimum acceptable price.
消费者剩余是消费者支付的价格低于其最高支付意愿时获得的额外好处。生产者剩余是生产者以高于其最低接受价格出售时获得的额外好处。
At competitive equilibrium, the sum of consumer and producer surplus – total community surplus – is maximised. This is allocative efficiency, where price equals marginal cost.
在竞争性均衡点，消费者剩余与生产者剩余之和——社会总剩余——达到最大化。这就是配置效率，此时价格等于边际成本。
To spot deadweight loss, look for a divergence from the equilibrium quantity. Taxes, subsidies and price controls typically create a wedge between the demand price and the supply price, shrinking the total surplus.
要发现无谓损失，只需寻找偏离均衡数量的情形。税收、补贴和价格管制通常会拉开需求价格与供给价格的差距，从而缩小总剩余。
Memory shortcut: Imagine total surplus as a pie; a deadweight loss is the slice that disappears because trade that could have made both sides better off no longer happens.
记忆捷径：把总剩余想象成一个馅饼；无谓损失就是因为原本能让双方获益的交易不再发生而消失掉的那一块。
5. Market Failure: Externalities and Public Goods | 市场失灵：外部性与公共物品
Market failure occurs when the free market, left alone, fails to allocate resources efficiently. The three most cited causes in WJEC are externalities, public goods and information gaps.
Published by TutorHao | Year 12 Economics Revision Series | aleveler.com
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