完形填空

　　Once there was no money. If people wanted to get 1 they had to 2 something. This is the way it used to be (以前就是这样). “I will give you my cow 3 your pig,” a man would say. “I'll give you my bowl 4 you 5 me a shirt,” another would say. “Here 6 seven oranges for one fish. ”“Will you give me a chicken for 7 ?”

　　People had to trade (交换、买卖) things 8 . They had to give a thing to get a thing 9 there wasn't 10 ．But they had to work out a good trade (公平交易) that came out even (平等交换) . What could you get for two chickens? Were three 11 a good trade for two bags of grapes (葡萄)? Or one bag of apples for a little meat? What was an even trade? It was 12 to know.

　　And it was 13 carry around all the things for trading. People had 14 too 15 getting things they needed. So they thought of a new way to trade.

　　They thought of money. Money could “stand for (代表)” apples, or bowls, or pigs. And a pocketful (口袋 ) of money was 16 than a pocketful of pigs! With money, it was not so hard to trade. 17 could use money. The man who needed a pig could 18 it with money. The man who sold the pig could keep the money until he needed something. People could work 19 money, and people could buy things with the money they got from 20 .

　　That is how it was, and that is how it is now.

1．

[　　]

2．

[　　]

3．

[　　]

4．

[　　]

5．

[　　]

6．

[　　]

7．

[　　]

8．

[　　]

9．

[　　]

10．

[　　]

11．

[　　]

12．

[　　]

13．

[　　]

14．

[　　]

15．

[　　]

16．

[　　]

17．

[　　]

18．

[　　]

19．

[　　]

20．

[　　]

[　　]