题目内容：

阅读下列短文，改正错误

People use money to buy food, books, bicycles and hundred      21.1.

of other things they need. When they work, they get pay in        22.2.

money. Most of the money used today are made of metal

or paper. So in ancient times(古代) people used all kinds         23.3.

of things as money. One of the first kind of money was           24.4.

shells. In China, cloth and knife were used as money .            25.5.

Elephant tusks, monkey tails and salt were used in African countries.

Cows and the other animals were used as money,too.             26.6.

The first copper coins were made in China.They are round.         27.7.

and had a square hole in the center. Different countries used

different metals for their money. Later some countries  began

to make coins by something expensive. The Chinese were         28.8.

the first to use paper money.The first paper  money were          29.9.

looked more likely a note than paper money used today.           30.10.