中国大学MOOC: Economists study the interactions between households and businesses and look at the ways in which the factors of production are combined to produce the goods and services that people need.

18) According to the circular flow model A: . in the market for goods and services, households are buyers and firms are sellers. B: . the market for goods and services, households are sellers and firms are buyers. C: . in the market for factors of production, households are buyers and firms are sellers. D: . firms are the owners of the factors of production.

The circular-flow diagram illustrates that, in markets for the factors of production, ( ) A: households are sellers, and firms are buyers. B: households are buyers, and firms are sellers. C: households and firms are both buyers. D: households and firms are both sellers.

Major influence factors on business purchase staff are: environment factors, organizational factors, factors, individual factors and Internet factors.

The long run A: means a long period of time, always longer than a year. B: is a period of time in which all factors of production can be varied. C: is different for different firms. D: Both answers B and C are correct.