1、单选题：
The opportunity cost of an item is ( ).
选项：
A:the time you have to spend on earning enough money to buy that item
B:what you give up to get that item
C:the price of that item
D:the cost of producing that item
答案: 【what you give up to get that item】

2、多选题：
Which of the following are reasons for scarcity? ( )
选项：
A:People’s money is limited.
B:People always ask for more.
C:People like to buy good quality stuff.
D:People live in a society that is not fair.
答案: 【People always ask for more.;
People like to buy good quality stuff.】

3、多选题：
Economics studies ( ).
选项：
A:how people make decisions
B:how people interact with one another
C:the forces and trends that affect the economy as a whole
D:how much people work, what they buy, how much they save and how they invest their savings
答案: 【how people make decisions;
how people interact with one another;
the forces and trends that affect the economy as a whole;
how much people work, what they buy, how much they save and how they invest their savings】

4、判断题：
Scarcity is the condition that a society does not have enough resources to produce all the things people would like to have. ( )
选项：
A:对
B:错
答案: 【对】

5、判断题：
Rich people can have unlimited resources because they have enough money to buy anything. ( )
选项：
A:对
B:错
答案: 【错】