scarcity稀缺性

The basic economic problem基本经济问题

opportunity cost机会成本

economic system经济体系

什么是稀缺性？

It is a situation in which there are too few resources to meet all human wants

我们该怎样做？

we must choose between options

经济学：1.microeconomics

     2.macroeconomics

choosing one thing means giving up something else in exchange

this is called trade-offs

Therefore， economics focus only on the most important trade-off

This is opportunity cost. It is the benefits lost from the next best alternative/choice.