Supply and demand describes how the amount sellers offer and the amount buyers want together set a price. When buyers want more than is available, prices rise; when supply exceeds demand, they fall.
供求关系讲的是：卖方愿意提供的数量和买方想要的数量，共同决定了价格。想要的多于能提供的，价格就涨；供给超过需求，价格就跌。
Most price stories are supply or demand stories in disguise. Oil rising because a refinery shut is supply; rising because Chinese drivers bought more cars is demand. The distinction matters because policy responds differently: supply shocks push inflation up and growth down, while demand can be cooled by higher rates without much output loss.
大多数价格新闻，本质都是供给故事或需求故事：炼厂停产让油价涨，是供给；中国消费者多买了车让油价涨，是需求。
这个区分很重要，因为政策反应不同：供给冲击会同时推高通胀、压低增长；需求过热则可以靠加息降温，产出损失不大。
High price means high demand
It can mean scarce supply. Price alone does not tell you which.
Supply and demand set a fair price
It sets a clearing price, not a just one.
Demand is want
Demand is want backed by ability to pay, at a given price.
· supply outpaces demand
· demand outstrips supply
· clear the market
· a supply shock
supply outpaces demand 供给超过需求；demand outstrips supply 需求压过供给；clear the market 出清市场；a supply shock 供给冲击。
· demand vs quantity demanded
· supply shock vs demand shock
demand 指整条需求曲线，quantity demanded 指某个价格上的购买量；供给冲击和需求冲击对价格与数量的影响方向不同。
Prices are set by supply and demand, and supply has been tight since X.
解释价格成因的常用句式：价格由供求决定，而供给自 X 以来一直偏紧。