机会成本是什么?

　　Economics is the study of choices leading to the best possible use of scarce resources in order to best satisfy unlimited human needs and wants.

　　首先来重温一下经济学的概念，经济物品是有限的，而人类的欲望是无限的，有限的经济物品总是难以满足无限产生和膨胀的人类欲望，这一矛盾就是经济学中的稀缺性。

　　一片土地，我们可以选择来种菜，也可以选择来盖楼房，根据土地的天时地利人和等因素作出使其利润化的判断和选择，限度地满足人类的欲望和需求，这就是咱们经济学研究的核心内容。

　　In microeconomic theory, the opportunity cost, also known as alternative cost, is the value (not a benefit) of the choice of a best alternative cost while making a decision.

　　在生活中，我们得在许多事情上作出权衡取舍，天下没有免费午餐。

　　我们的世界很奇妙，它既不能让我们随心所欲，却也不至于让我们只有一条路可走，每个人面前都有着可供选择的余地。但最残酷的往往是为了得到一种心爱的东西必需忍痛割爱，正所谓“鱼和熊掌不可兼得”，为了得到一样东西，我们必须放弃的次优选择，就是机会成本。

　　小测一下

　　下面准备了一道ap考试题，大家来测试一下自己对这个知识点对掌握程度吧～

　　Nancy has the choice to spend one hour studying for an exam, mowing the lawn for one hour at a wage of $6, or babysitting her niece for one hour at a wage of $8. If we know that Nancy has chosen to study for the exam, which of the following is true?

　　(A) The benefit received from studying is greater than the opportunity cost of $8.

　　(B) The opportunity cost of studying is $14, which is less than the benefit received from studying.

　　(C) Nancy is indifferent to both studying and mowing the lawn.

　　(D) Nancy’s behavior is irrational, since babysitting was clearly superior to all other options.

　　(E) Nancy is indifferent to both babysitting and mowing the lawn.