allocative efficiency occurs when social welfare is maximised. The distribution of resources is such that it is not possible to redistribute them without making someone worse off.
当社会福利最大化时即实现配置效率。此时资源的分配使得任何重新分配都必然使某人境况变差。
人话『资源配置到了最该去的地方』—— 想再优化就必须损害别人。
swapping one good for another without the use of money.
不使用货币，以一种商品直接交换另一种商品。
人话没有货币时的交易方式。它的致命缺陷：需要『双向巧合』。
resources have to be allocated between competing uses because wants are infinite but resources are scarce.
由于欲望无限而资源稀缺，资源必须在相互竞争的各种用途之间进行分配。
人话一切经济学的起点：想要的无止境，能用的有限，所以必须做选择。
a branch of economics that accepts that consumers and other economic agents do not always act rationally and looks at why this might be so.
经济学的一个分支，承认消费者及其他经济主体并不总是理性行事，并探究其原因。
人话承认人会犯傻，并研究『为什么傻』。它是对『理性人』假设的修正。
as a factor of production is the stock of manufactured resources used in the production of goods and services.
作为生产要素，指用于生产商品与服务的、已制造出来的资源存量。
人话生产用的『人造工具』：机器、厂房、设备。注意它不是钱。
goods that are used in the production of other goods, such as factories, offices, roads, machines and equipment.
用于生产其他商品的商品，如厂房、办公室、道路、机器与设备。
人话造『用来造东西的东西』。买资本品=投资，是增长的来源。
output per unit of capital employed.
单位已用资本的产出。
人话衡量机器设备用得值不值。
all things being equal; the assumption that, while the effects of a change in one variable are being investigated, all other variables are kept constant.
其他条件不变；即假定在研究某一变量变化的影响时，其余所有变量保持不变。
人话经济学做分析时的『先按住其他变量不动』。不这么约定，就永远说不清是谁导致了什么。
economic choices involve the alternative uses of scarce resources.
经济选择涉及稀缺资源在多种替代用途之间的取舍。
人话因为稀缺所以必须放弃点什么 —— 这就是机会成本的来源。
or planned or centrally planned economy: an economic system where government, through a planning process, allocates resources in society.
（或称计划经济、中央计划经济）由政府通过计划过程配置社会资源的经济制度。
人话政府说了算。优点是能集中力量，缺点是常常配错、还缺乏创新动力。
goods and services that are used by people to satisfy their needs and wants.
被人们用来满足需要与欲望的商品与服务。
人话直接让人用的最终产品。它和资本品的区别在于『谁用它』。
a digital or virtual currency that uses cryptography as security, thereby making it secure.
使用密码学作为安全保障的数字或虚拟货币，并因此具备安全性。
人话去中心化的数字货币。它缺少央行背书，所以价格波动极大。
the amount of money you have left to spend after you have paid your taxes, bills etc.
缴纳税款、账单等之后剩下可用于支出的收入。
人话到手能花的钱。它是消费函数里最关键的自变量之一。
specialisation by workers, who perform different tasks at different stages of production to make a good or service, in co-operation with other workers.
工人之间的专业化：在生产的不同阶段与其他工人协作，各自完成不同任务以产出商品或服务。
人话把一件活拆成多道工序，每人只干一道。效率高，但工人会变『螺丝钉』。
goods that are scarce because their use has an opportunity cost.
因其使用具有机会成本而稀缺的商品。
人话有代价才能拿到的东西。绝大部分商品都是经济品。
a complex network of individuals, organisations and institutions and their social and legal inter-relationships which allocate resources.
由个人、组织与机构及其社会与法律关系构成的、负责配置资源的复杂网络。
人话一个社会『怎么决定生产什么、怎么分』的一整套机制。
the level of well-being or prosperity or living standards of an individual or group of individuals such as a country.
个人或群体（如一个国家）的福祉、繁荣或生活水平。
人话日子过得好不好。它不只看钱，还包括健康、环境等。
based on scientific testing or practical experience, not on ideas.
基于科学检验或实践经验，而非基于主观想法。
人话『做过实验、有数据撑着』的，与『想当然』相对。
as a factor of production is the seeking out of profitable opportunities for production and taking risks in attempting to exploit these.
作为生产要素，指主动寻找有利可图的生产机会，并承担风险去加以利用。
人话四要素里最『主动』的那个：不是干活，是找机会 + 担风险。
individuals who seek out profitable opportunities for production and take risks in attempting to exploit these.
寻找有利可图的生产机会并承担风险去利用这些机会的个人。
人话拍板投钱、扛风险的那个人。
in a company, is the value of the assets owned by the shareholders.
在公司中，指股东所拥有的资产价值。
人话股东在公司里真正占有的那份价值。会计上=资产−负债。
the inputs to the production process: land, labour, capital and enterprise or entrepreneurship.
生产过程的投入，包括：土地、劳动、资本和企业家才能。
人话做生意的四样『原料』，缺一样都转不起来。
any convenient set of arrangements where buyers and sellers can buy or trade a range of services or assets that are fundamentally monetary in nature.
买方与卖方可以购买或交易一系列本质上属于货币性质的服务或资产的任何便利安排。
人话钱和金融资产（股票、债券、外汇）交易的地方。银行、交易所都是。
economic resources, such as factories and hospitals, that are used to transform working capital into goods and services.
厂房、医院等经济资源，用于把流动资本转化为商品与服务。
人话厂房机器这类『长期趴在那不动』的资本。
goods that are unlimited in supply and therefore have no opportunity cost.
供给无限因而没有机会成本的商品。
人话空气这种不用抢的东西。现实中极少，所以考试里要能区分。
or free enterprise economy or capitalist economy or market economy: an economic system that resolves the basic economic problems mainly through the market mechanism.
（或称自由企业经济、资本主义经济、市场经济）主要通过市场机制来解决基本经济问题的经济制度。
人话价格自己说了算，政府尽量不插手。
a thing that is produced in order to be sold.
为出售而生产出来的物品。
人话最基础的经济学对象：生产出来就是为了卖的东西。
the rational human used by economists when constructing, explaining and verifying models.
经济学家在构建、解释和验证模型时所使用的『理性人』。
人话一个理论上的理想消费者：永远算得清、永远选最优。现实中并不存在。
the value of the productive potential of an individual or group of workers; it is made up of the skills, talents, education and training of an individual or group and represents the value of future earnings and production.
个人或劳动者群体生产潜力的价值，由技能、天赋、教育与培训构成，代表未来收入与产出的价值。
人话把『人的本事』当成一种资本来看：受教育=给自己投资。
an idea that is suggested as an explanation for something, but that has not yet been proved to be true.
为解释某事而提出的、尚未被证实为真的想法。
人话还没被证实的解释。被证实了就升级为理论。
difficult to convert an asset into cash. Completely illiquid means it is impossible to do so.
难以将资产变现为现金；完全缺乏流动性意味着根本无法变现。
人话想卖卖不掉，或一卖就大亏。房子就是典型的低流动性资产。
an unfair situation, in which some groups in society have more money, opportunities, or power than others.
一种不公平的状况：社会中某些群体比其他人拥有更多金钱、机会或权力。
人话分配上的不公平。注意它是『规范性』议题，涉及价值判断。
as a factor of production is the workforce.
作为生产要素，指劳动力。
人话四要素里的『人』。
output per worker.
每位工人的产出。
人话衡量人的效率。它涨了，工资才可能真涨。
as a factor of production is all natural resources.
作为生产要素，指一切自然资源。
人话四要素里唯一『天生就有』的，且供给基本固定。
a theory or model that has been verified by empirical evidence.
已被经验证据验证的理论或模型。
人话验证过关的理论。经济学里敢叫『定律』的很少。
the ability to change an asset into cash. The more liquid an asset is, the easier it is to do this.
将资产转换为现金的能力；资产流动性越高，越容易变现。
人话『变现的容易程度』。现金流动性最高，古董最低。
a point of possible change.
一个可能发生变化的临界点。
人话『再多一点/再少一点』的那个点上。经济学一切决策都是边际决策。
focuses on small or incremental changes in an economic variable such as cost or output.
关注成本或产出等经济变量的微小或增量变化。
人话只算『多做/少做一个』的得失，而不是算总量。
the study of the behaviour of individuals or groups such as consumers, firms or workers, typically within a market context.
研究个人或群体（如消费者、企业或工人）的行为，通常置于市场情境中。
人话看『个体』：某个市场、某家企业的定价与决策。
an economy where both the free market mechanism and the government planning process allocate significant proportions of total resources.
自由市场机制与政府计划过程各自配置相当大比例总资源的经济。
人话现实中几乎都是这种：市场为主、政府补位。
any item, such as a coin or a bank balance, which fulfils four functions: a medium of exchange, a measure of value, a store of value and a method of deferred payment.
任何能满足四项职能的物品（如硬币或银行存款）：交换媒介、价值尺度、价值储藏与延期支付手段。
人话记住这四大职能 —— 尤其『价值储藏』，它解释了通胀为何伤害货币。
anything that can be used as a medium of exchange but are not stores of value. Examples are charge cards or credit cards.
任何可作为交换媒介但不是价值储藏手段的东西，例如签账卡或信用卡。
人话能拿来付款，但本身不『存』价值。刷卡不等于货币。
the minimum that is necessary for a person to survive as a human being.
人作为人得以生存所必需的最低限度。
人话不满足会活不下去的。和 wants（欲望）相对。
a theory of economics that typically starts with the assumption that economic agents will maximise their benefits and act rationally, and that develops how resources will be allocated in markets and at what price through the forces of demand and supply, the margin is a key concept in neo-classical theory.
一种经济学理论，通常从『经济主体会最大化自身利益并理性行事』的假设出发，进而说明资源如何在市场中、以何价格经供求力量完成配置；边际是新古典理论的核心概念。
人话主流教科书经济学：假设人人理性、市场自然出清。边际分析是它的看家本领。
resources, such as coal or oil, which once exploited cannot be replaced.
煤炭、石油等一旦开采便无法再生的资源。
人话用完就没有了。这是可持续增长议题的物理底线。
a resource which that can be economically exploited in such a way that its stock is being reduced over time.
其存量因经济性开采而随时间减少的资源。
人话还在用，但越用越少 —— 强调的是『使用方式不可持续』。
the study and presentation of policy prescriptions involving value judgements about the way in which scarce resources are allocated.
研究与表述涉及价值判断的稀缺资源配置政策主张。
人话回答『应该怎样』。带主观好坏判断，无法用数据证明对错。
statements that cannot be supported or refuted because it is a value judgement.
因属于价值判断而既无法被支持、也无法被驳倒的陈述。
人话『应该/不应该』型句子。对错取决于立场，不是事实。
the benefits of the next best alternative that are given up.
所放弃的次优选择所能带来的收益。
人话选 A 就得放弃 B，B 的价值就是 A 的代价。经济学第一个必考定义。
the scientific or objective study of the allocation of resources.
对资源配置的科学或客观研究。
人话回答『是什么』。可以用事实检验真假。
statements that can be supported or refuted by evidence.
可以用证据支持或反驳的陈述。
人话『事实型』句子，能拿数据打脸或坐实。
a curve that shows the maximum potential level of output of one good, given a level of output for all other goods in the economy.
在给定经济中所有其他商品产出水平的条件下，显示某一种商品最大潜在产出水平的曲线。
人话（同 eco_01）资源用满时的各种产出组合。
output per unit of input employed.
每单位所投入要素的产出。
人话『投一得几』。它是长期增长的真正引擎 —— 比多投人更根本。
resources, such as fish stocks or forests, that can be exploited over and over again because they have the potential to renew themselves.
鱼群、森林等因具备自我更新潜力而可反复利用的资源。
人话只要不捞绝砍光，就能自己长回来。关键是『可持续的速率』。
banks that provide services to individuals.
为个人提供服务的银行。
人话面向你我这种普通人的银行（存钱、贷款、开卡）。
resources that are limited in supply so that choices have to be made about their use.
供给有限、因而必须就其用途做出选择的资源。
人话经济学意义上的『稀缺』= 不够所有人免费随便用，与数量多少无关。
a method that subjects theories or hypotheses to being disproved by empirical evidence.
让理论或假说接受经验证据证伪的方法。
人话靠『能不能被推翻』来筛选理论，而不是靠权威。
the study of societies and human behaviour using a variety of methods, including the scientific method.
使用多种方法（包括科学方法）研究社会与人类行为的学科。
人话经济学属于社会科学：研究对象是人，不能像物理那样完全控制变量。
a system of organisation where economic units such as households or nations are not self-sufficient but concentrate on producing certain goods and services and trading the surplus with others.
一种组织形式：家庭或国家等经济单位不再自给自足，而是集中生产特定商品与服务，并将剩余部分与他人交易。
人话只做自己最擅长的那件事，剩下的靠交换。分工的基础。
a model or hypothesis that is capable of being refuted by empirical evidence.
能够被经验证据推翻的模型或假说。
人话『可被证伪』才配叫理论 —— 这是它和宗教式信念的分界线。
desires for the consumption of goods and services.
对消费商品与服务的愿望。
人话想要的。它无限，这是所有经济问题的源头。
or circulating capital: resources that are in the production system waiting to be transformed into goods or other materials before being finally sold to the consumer.
（或称流通资本）处于生产体系中、等待被转化为商品或其他材料、最终售予消费者的资源。
人话原料、半成品、库存这类『会被用掉变成产品』的资本。
goods that are purchased with other goods to satisfy a want. Complements have a negative cross elasticity of demand with each other.
为满足同一欲望而与其他商品一同购买的商品。互补品之间具有负的交叉需求弹性。
人话一起用的东西：打印机与墨盒。一个涨价，另一个也卖不动。
factors other than price, such as income or the price of other goods, which lead to changes in demand and are associated with shifts in the demand curve.
价格以外的因素（如收入或其他商品价格），它们导致需求变化，并表现为需求曲线的移动。
人话价格之外的『让整条需求线搬家』的原因。注意区分 shift 和 movement。
when quantity demanded for a good falls because its price rises; it is shown by a movement up the demand curve.
当某商品价格上升导致其需求量下降时，表现为沿需求曲线向上移动。
人话只有『价格自己变了』引起的减少才叫 contraction，不叫 shift。
or cross-price elasticity of demand: a measure of the responsiveness of quantity demanded of one good to a change in price of another good. It is measured by dividing the percentage change in quantity demanded of one good by the percentage change in price of the other good.
（或称交叉价格弹性）衡量一种商品的需求量对另一种商品价格变化的反应程度。用一商品需求量的百分比变化除以另一商品价格的百分比变化来衡量。
人话判断 A、B 到底是替代还是互补的量具：正=替代，负=互补。
or effective demand: the quantity purchased of a good at any given price, given that other factors of demand remain unchanged.
（或称有效需求）在其他需求因素不变的条件下，任一给定价格下所购买的商品数量。
人话『有购买力支撑的想要』才是需求。只有愿望不算。
the line on a price/quantity diagram that shows the level of effective demand at any given price.
价格／数量图上显示任一给定价格下有效需求水平的曲线。
人话向右下倾斜的那条线：价越高，想买的人越少。
where the price elasticity of demand is greater than 1. The responsiveness of demand is proportionately greater than the change in price. Demand is perfectly elastic if price elasticity of demand is infinity.
需求价格弹性大于 1。需求的反应幅度按比例大于价格变化幅度。若需求价格弹性为无穷大，则为完全富有弹性。
人话价格动一点，需求量动更多。降价反而能多赚，说的就是它。
when quantity demanded for a good increases because its price falls; it is shown by a movement down the demand curve.
当某商品价格下降导致其需求量增加时，表现为沿需求曲线向下移动。
人话价格跌了所以多买了 —— 还在同一条线上动，不是搬家。
a measure of the responsiveness of quantity demanded to a change in income. It is measured by dividing the percentage change in quantity demanded by the percentage change in income.
衡量需求量对收入变化的反应程度。用需求量的百分比变化除以收入的百分比变化来衡量。
人话收入涨了，这货多卖还是少卖？正=正常品，负=劣等品。
where the price elasticity of demand is less than 1. The responsiveness of demand is proportionately less than the change in price. Demand is perfectly inelastic if price elasticity is zero.
需求价格弹性小于 1。需求的反应幅度按比例小于价格变化幅度。若弹性为零，则为完全缺乏弹性。
人话价格动很多，需求量几乎不动。必需品、成瘾品常见。
goods for which demand falls when income increases (i.e. it has a negative income elasticity of demand).
当收入增加时需求反而下降的商品（即具有负的需求收入弹性）。
人话有钱了就不买了（泡面、廉价替代品）。注意『劣等』不带贬义，纯粹是弹性符号。
the value or utility that individual consumers gain from the last product consumed falls the greater the number consumed. So the marginal utility of consuming the sixth product is lower than the second product consumed.
消费者从最后一个被消费产品中获得的价值或效用，随消费数量增加而下降。因此消费第 6 个产品的边际效用低于第 2 个产品。
人话越吃越不香。它是需求曲线向下倾斜的深层解释。
factors, other than price, that affect the demand for a good or service.
价格以外、影响某商品或服务需求的因素。
人话让需求曲线整条搬家的那些原因（收入、偏好、相关品价格）。
goods for which demand increases when income increases (i.e. has a positive income elasticity of demand).
当收入增加时需求也增加的商品（即具有正的需求收入弹性）。
人话有钱了买更多。绝大多数商品都是正常品。
or own price elasticity of demand: the proportionate response of changes in quantity demanded to a proportionate change in price, measured by the formula: (P/Qd) × (ΔQd/ΔP).
（或称自身价格弹性）需求量变化对价格变化的比例反应，用公式 (P/Qd)×(ΔQd/ΔP) 衡量。
人话『价格变 1%，需求量变几%』。它是定价决策的核心参数。
a movement of the whole demand curve to the right or left of the original caused by a change in any variable affecting demand except price.
由价格以外的任何影响需求的变量变化所引起的、整条需求曲线相对原位置向右或向左的移动。
人话整条线搬家（非价格因素）。右移=更想买，左移=更不想买。
goods that can be replaced by another to satisfy a want. Substitutes have a positive cross elasticity of demand with each other.
可以被另一种商品取代以满足同一欲望的商品。替代品之间具有正的交叉需求弹性。
人话二选一的东西：可口可乐与百事。一个涨价，另一个就卖得好。
quantity bought multiplied by the average price of a product.
购买数量乘以产品的平均价格。
人话买家总共花了多少钱。它和总收益是同一笔钱的两种视角。
where the value of price elasticity of demand is 1. The responsiveness of demand is proportionally equal to the change in price.
需求价格弹性等于 1。需求的反应幅度按比例等于价格变化幅度。
人话价格与需求量同比例反向变化，总收益刚好不变。分界线。
the satisfaction or benefit derived from consuming a good or a set of goods.
从消费某商品或某组商品中所获得的满足或收益。
人话『爽的程度』。注意：效用是主观的，无法直接测量。
factors other than price, such as income or the price of other goods, that lead to changes in supply and are associated with shifts in the supply curve.
价格以外的因素（如收入或其他商品价格），它们导致供给变化，并表现为供给曲线的移动。
人话价格之外的『让整条供给线搬家』的原因。
the period of time in which all factor inputs can be varied but the state of technology remains constant.
所有要素投入均可变动、但技术水平保持不变的时间段。
人话长到连厂房设备都能改。注意：技术仍然不许变。
a measure of the responsiveness of quantity supplied to a change in price. It is measured by dividing the percentage change in quantity supplied by the percentage change in price.
衡量供给量对价格变化的反应程度。用供给量的百分比变化除以价格的百分比变化来衡量。
人话涨价了，厂家能多快多产出多少。产能受限的行业弹性低。
the period of time when at least one factor input to the production process can be varied.
生产过程中至少有一种要素投入可以变动的时间段。
人话短到只能改一部分（比如多雇人），厂房还动不了。
a grant given that lowers the price of a good, usually designed to encourage production or consumption of a good.
为降低商品价格而给予的补助，通常旨在鼓励该商品的生产或消费。
人话政府倒贴钱让价格降下来，用来鼓励某些行为（如新能源）。
the quantity of goods that suppliers are willing to sell at any given price over a period of time.
供给方在一定时期内任一给定价格下愿意出售的商品数量。
人话卖家肯卖多少。价格越高通常越肯卖（曲线向上）。
tax charged as a percentage of the value of the good.
按商品价值的一定百分比征收的税。
人话按价格百分比收（如 VAT 20%）。价格越高，税额越高。
the difference between how much buyers are prepared to pay for a good and what they actually pay.
买方愿意为某商品支付的金额与其实际支付金额之间的差额。
人话『我本来愿意出 100，结果只花了 70』—— 赚到的 30。福利分析的基本工具。
the price at which there is no tendency to change because planned (or desired or ex ante) purchases (i.e. demand) are equal to planned sales (i.e. supply).
计划（或意愿、事前）购买量等于计划销售量的价格，此时价格没有变动趋势。
人话想买的数量正好等于想卖的数量，价格就此安顿下来。
where demand is greater than supply.
需求大于供给。
人话想买的人多于能买到的量 —— 价格被往上顶。
where supply is greater than demand.
供给大于需求。
人话东西卖不掉 —— 价格被往下压。
forces in free markets that act to reduce prices when there is excess supply and raise prices when there is excess demand.
自由市场中的力量：在超额供给时压低价格，在超额需求时抬高价格。
人话市场自带的自动调节器，不需要谁下命令。
when changes in price encourage buyers and sellers to change the quantity they buy and sell. A rise in price encourages buyers to purchase less and sellers to produce more; and vice versa.
价格变化促使买卖双方改变其买卖数量。涨价使买家少买、卖家多产；反之亦然。
人话价格是根指挥棒：涨价=叫你多产少买。
the tax burden on the taxpayer.
落在纳税人身上的税收负担。
人话这笔税最终是谁掏的 —— 名义上收企业，实际常转嫁给消费者。
any convenient set of arrangements by which buyers and sellers communicate to exchange goods and services.
买方与卖方借以沟通并交换商品与服务的任何便利安排。
人话重点不在『地点』而在『买卖双方碰头的方式』—— 网购也是市场。
the price at which there is neither excess demand nor excess supply, but where everything offered for sale is purchased.
既无超额需求也无超额供给、所有待售商品均被买走的价格。
人话『卖的一件不剩、买的一个不落』的价格，实质就是均衡价格。
the difference between the market price that firms receive and the price at which they are prepared to supply.
企业所获得的市场价格与其愿意供给的价格之间的差额。
人话『我本来 70 就肯卖，结果卖了 100』—— 多赚的 30。
when changes in price lead to more or less being produced, so increasing or limiting the quantity demanded by buyers.
价格变化导致产量增减，从而增加或限制买方的需求量。
人话价格用『贵不贵』来筛人，把有限的货分配给出得起价的人。
when changes in price give information to buyers and sellers that influence their decisions to buy and sell.
价格变化向买卖双方传递信息，影响其买卖决策。
人话价格会『喊话』：这里缺货/这里过剩。它是最廉价的情报系统。
or unit tax: tax charged on volume.
（或称单位税）按数量征收的税。
人话按件收（每包烟 5 元），不随价格变。
a market that is a distinct and identifiable part of a larger market.
较大市场中的一个独立且可辨识的部分。
人话大市场里的一块细分地带，例如『电动车』之于『汽车』。
quantity sold multiplied by the average price of a product.
销售数量乘以产品的平均价格。
人话卖家总共收到多少钱。判断该不该涨价就看它。
when information is not shared equally between buyer and seller and one side has an advantage.
买卖双方信息不共享，其中一方占据优势。
人话一方知道的比另一方多 —— 二手车卖家比买家懂车就是典型。
when a market fails to supply any of a good that is demanded, creating a missing market.
市场未能供给任何有需求的商品，从而形成缺失市场。
人话整个市场根本不存在（比如没人愿意提供国防），不是『供多供少』的问题。
or external benefits of consumption: when the social costs of consumption are different from the private costs of consumption.
（或称消费的外部收益）当消费的社会成本不同于消费的私人成本时。
人话你消费时，顺带影响到别人（好或坏），而你没为此付钱或收钱。
or spillover effect: the difference between social costs and benefits and private costs and benefits.
（或称溢出效应）社会成本与收益同私人成本与收益之间的差额。
人话你的行为对第三方的影响，且这个影响没被计入价格。
a person or organisation that receives benefits that others have paid for without making any contributions.
接受他人付费所提供的收益，却未作任何贡献的个人或组织。
人话自己不掏钱，蹭别人买好的公共服务 —— 公共品供给不足的根源。
where buyers or sellers or both lack information to make an informed decision.
买方或卖方或双方缺乏信息以做出明智决策。
人话信息不够，只能瞎猜。它本身就是一种市场失灵。
or information gap: where buyers or sellers or both do not have the information that is available to make a decision.
（或称信息缺口）买方或卖方或双方未掌握可用于决策的现有信息。
人话信息其实存在，但一方拿不到。二手车的『柠檬市场』就是这么来的。
the social and private costs and benefits of the last unit either produced or consumed.
最后一单位被生产或消费的商品所带来的社会与私人成本及收益。
人话决策看边际：MSC=MPC+外部成本，MSB=MPB+外部收益。判断是否失灵就看这两条线的交点。
occurs when rising demand drives prices beyond the level that might normally be expected.
当需求上升把价格推高到超出通常预期水平时发生。
人话价格靠『大家觉得还会涨』撑着，脱离基本面，终会破。
where resources are inefficiently allocated due to imperfections in the working of the market mechanism.
因市场机制运行存在缺陷而导致资源被低效配置。
人话市场自己搞砸了：该多产的不产、该少产的多产。政府干预的理由。
a market where the market mechanism fails to supply any of a good.
市场机制未能供给任何该商品的市场。
人话完全市场失灵的产物：这个市场压根就没有。
when an economic agent makes a decision in their own best interest knowing that there are potential negative risks, and that if problems result, the cost will be partly paid by other economic agents.
当经济主体明知存在潜在负面风险、且问题一旦发生成本将由其他经济主体部分承担时，仍作出有利于自身利益最大化的决策。
人话『反正有人兜底，我就冒险』。保险与救助机制下的经典问题。
when social benefits are less than private benefits.
社会收益小于私人收益时。
人话你爽了，但邻居遭殃（如吸烟）。消费的『外部成本』。
or external cost: exist if net social cost (social cost minus social benefit) is greater than net private cost (private cost minus private benefit).
（或称外部成本）当净社会成本（社会成本−社会收益）大于净私人成本（私人成本−私人收益）时存在。
人话这笔交易让第三方受损，而价格里没体现。典型：污染。
when social costs exceed private costs.
社会成本超过私人成本时。
人话工厂排污：它自己只算私账，社会却要替它买单。
once provided, it is impossible to prevent any economic agent from consuming the good.
一旦被提供出来，就无法阻止任何经济主体消费该商品。
人话挡不住别人用（如路灯）。导致没法收费。
once provided, it is impossible for any economic agent not to consume the good.
一旦被提供出来，任何经济主体都无法不消费该商品。
人话想不用都不行（如国防、清洁空气）。
or non-diminishability or non-exhaustability: consumption by one economic agent does not reduce the amount available for consumption by others.
（或称不可减损性、不可耗尽性）一个经济主体的消费不会减少可供他人消费的数量。
人话你用不影响我用（我看电视不妨碍你看）。所以多一个人用的边际成本≈0。
when a market for a good exists but there is too much or not sufficient production of the good.
某商品的市场存在，但该商品生产过多或不足。
人话市场在，但量不对（太多或太少）。比完全失灵常见得多。
when social benefits exceed private benefits.
社会收益超过私人收益时。
人话你消费，别人也受益（如打疫苗）。所以常需要补贴鼓励。
or external benefit: exist if net social benefit is greater than net private benefit.
（或称外部收益）当净社会收益大于净私人收益时存在。
人话这笔交易让第三方受益，而价格里没体现。典型：教育。
when social costs are less than private costs.
社会成本小于私人成本时。
人话企业生产时顺手造福了社会，但自己没拿到好处，所以往往产出不足。
occurs when the goals of principals, those who would gain or lose from a decision, are different from agents, those making decisions on behalf of the principal. Examples include shareholders (principals) and managers (agents), or children (principals) and parents (agents).
当委托人（从决策中获益或受损者）的目标与代理人（代表委托人作决策者）的目标不一致时产生。例如股东（委托人）与经理（代理人），或子女（委托人）与父母（代理人）。
人话出钱的人和不干活的决策人对不上心 → 代理人可能为自己谋利。
the cost or benefit of an activity to an individual economic unit such as a consumer or a firm.
某项活动对消费者或企业等单个经济单位所造成的成本或收益。
人话只算到自己头上的那部分账。
goods that possess the characteristics of rivalry (once consumed, it cannot be consumed by any one else) and excludability (it is possible to prevent someone else from consuming the good).
同时具备竞争性（一旦被消费，他人便无法再消费）与排他性（可以阻止他人消费）的商品。
人话又抢得走又挡得住 —— 所以市场能正常买卖。面包就是私人品。
or external benefits of production: when the social costs of production are different from the private costs of production.
（或称生产的外部收益）当生产的社会成本不同于生产的私人成本时。
人话生产过程溢出的影响，不管好坏。
theories about how and why public spending and taxation decisions are made.
关于公共支出与税收决策如何以及为何作出的理论。
人话把政客和官僚也当『理性人』分析：他们也有私利。
or pure public goods: goods that possess the characteristics of non-rivalry (or non-diminishability) and non-excludability (which includes the characteristic of non-rejectability).
（或称纯公共品）同时具备非竞争性（或不可减损性）与非排他性（含非拒绝性）的商品。
人话两个特征缺一不可。因为收不上钱，市场不愿提供 → 必须由政府供。
or non-pure public goods: a good that does not fully possess the characteristics of non-rivalry and non-excludability and yet which also is not perfectly rival or excludable.
（或称非纯公共品）不完全具备非竞争性与非排他性，但也并非完全竞争或完全排他的商品。
人话半公共：像公园、收费公路 —— 平时不挤但会堵，也勉强能收费。
means buying or selling something in the expectation of a future price change and a profit.
为预期未来价格变动并获利而买卖某物。
人话赌价格差，不创造实际价值。它提供流动性，也可能放大泡沫。
occurs when the cost to the economy is so great that the government cannot allow it to happen.
当其倒闭对经济的代价大到政府无法任其发生时。
人话大到政府不敢让你倒 —— 于是道德风险登场，2008 年金融危机就是这么来的。
schemes that set a limit on a particular type of pollution, and then issue pollution permits to the total of that limit, which can be bought and sold between firms that pollute.
对特定类型污染设定总量上限，并按总量发放污染许可证，允许排污企业之间买卖这些许可证的机制。
人话政府定总量，企业间买卖额度。市场机制的环保版。
occurs when government intervention leads to a net welfare loss compared to the free market solution.
当政府干预相对于自由市场结果导致净福利损失时发生。
人话政府出手反而更糟。这是『市场失灵所以要管』的反面教材。
the use of political power by an economic agent to influence the distribution of resources for their own benefit at the expense of others without creating any extra wealth for society.
经济主体运用政治权力影响资源分配，以牺牲他人为代价谋取自身利益，且不为社会创造任何额外财富。
人话花力气去『抢蛋糕』而不是『做大蛋糕』。游说、拉关系换补贴就是。
or pollution permit or pollution credit: a permission issued, usually by a government, to allow a fixed amount of pollution to be created; this permit can be used by the owner or sold to another firm.
（或称排污许可、排污额度）通常由政府发放的许可，允许产生固定量的污染；该许可可由持有者自用或出售给其他企业。
人话一张『允许排多少污』的票。它的可交易性是关键 —— 减排成本低的企业会多减、卖票。
