经济学家认为,生产可能性边界经常呈凹向原点的曲线,因为
A. 权衡不可避免地造成失业。
B. 资源不是完全适应的。
C. 机会成本是不变的。
D. 技术进步。
“污染税可以减少企业产生的污染量”这一实证表述,
A. 可能由担任政策顾问的经济学家制定。
B. 需要价值观和数据才能进行评估。
C. 需要数据而不是价值观才能进行评估。
D. 不能由充当科学家的经济学家来评估。
[单选]An economy’s production possibilities frontier is also its consumption possibilities frontier
A. under all circumstances.
B. under no circumstances.
C. when the economy is self-sufficient.
D. when the rate of tradeoff between the two goods being produced is constant.
[单选]Regan grows flowers and makes ceramic vases. Jayson also grows flowers and makes ceramic vases, but Regan is better at producing both goods. In this case, trade could
A. benefit both Jayson and Regan.
B. benefit Jayson, but not Regan.
C. benefit Regan, but not Jayson.
D. benefit neither Jayson nor Regan.