Production possibility frontier and investment 生产可能性边界和投资

One choice an economy faces is between capital goods (investment) and consumer goods. 一个经济体面临的一个选择是在资本货物（投资）和消费品之间。

• If more resources are devoted to capital goods (e.g. building new factories) then in the short-term, consumption will go down. 如果将更多的资源用于资本货物（如建造新工厂），那么在短期内，消费将下降。
• However, if the investment is successful, then in the long-run, productive capacity will increase and the PPF curve will shift to the right 然而，如果投资是成功的，那么从长远来看，生产能力将增加，生产可能性边界曲线将向右移动。

Increase in capital goods has an opportunity cost of fewer consumer goods, but in long-term can enable economic growth. 增加资本货物有机会成本，即减少消费品，但从长远来看，可以使经济增长。

Similarly, a decline in investment can enable more consumer goods in the short-term but can lead to lower rates of economic growth. 同样，投资的减少在短期内可以使更多的消费品，但会导致经济增长率的降低。

A recession can be shown by output falling below the production possibility frontier (from A to B). 衰退可以表现为产出低于生产可能性前沿（从A到B）。

• A = full employment 充分就业
• B = unemployed resources 失业的资源

Any government faces a trade-off in how to use scarce resources and tax revenue. If the government increases spending on the military, then the opportunity cost will be less spending on another public service, such as health care. 任何政府都面临着如何使用稀缺资源和税收的权衡。如果政府增加军事开支，那么机会成本将是减少对另一项公共服务的开支，如医疗保健。

This shows a trade-off between working and hours spent in leisure.这显示了工作和休闲时间之间的权衡。