Colas and root beer are substitutes, and a fall in the price ofroot beer (resulting in an increase in the consumption of root beer) will tend to decrease the demandfor colas.

可乐和根啤是替代品，根啤价格的下降（因而引起根啤的消费量增加）会减少可乐的需求量。

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That suggests a high degree of price-inelasticity. Consumers will endure higher prices with respect to products for which there are perceived to be few substitutes.

这表明价格的刚性程度较高，也就是说，对于很少有替代性选择的产品来说，消费者会忍受较高的价格。

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Nevertheless, different products may beconsidered to be in a single market if the products are reasonable substitutes,and we can consider a “quality-adjusted” price for these different goods.

然而，即使是不同的商品，只要这些商品在某种程度上具有可替代性，也可以放在同一个市场上比较，对于这种商品，我们可以考虑使用“质量调整价格”进行比较。

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England paid the price for such profligacy as Sweden - galvanised by substitutes Labinot Harbuzi, Robin Soder and Molins - gradually chipped away at the deficit.

BBC: England U21 3-3 Sweden U21 (aet)

There are plenty of reasons that American demand for Chinese goods is price inelastic including, most importantly, that there are limited substitutes for those goods.

FORBES: Economists Ignore the Facts in Supporting Chinese Currency Legislation

So, when the price mechanism is allowed to work, consumption regulates itself and technology creates substitutes.

FORBES: Commodity Prices: Why Technology and the Price Mechanism will Prove the Scarcity Pessimists Wrong