The most pressing problem any economic system faces is how to use its scarce resources.
A. puzzling
B. difficult
C. terrifying
D. urgent
Sally likes to tease her brother about his girl friends.
A. charm
B. laugh at
C. criticize
D. respect
由企业购买任何生产要素所发生的成本是指( )
A. 显性成本
B. 隐性成本
C. 机会成本
D. 总成本
如果在需求曲线有一点,Ed= -2,P=20元,则MR为( )
A. 30元
B. 60元
C. -10元
D. 10元