任务型阅读
China has been the birthplace of many of the world's greatest inventions. It was, for example, the first country to produce paper money. Before the invention of paper money and coins, people used many different kinds of things for buying and selling. ____ This exchange of goods and services for other goods and services is called bartering（物物交换）.
____ In 1200 BC, people in China began to use shells as money. Usually the shells used as money were very small. This made it easier for people to carry money over long distances, and allowed for trade to develop between different parts of the country.
In the years which followed this invention, many other countries around the world began to do the same. ____
The next development was in 1000 BC, when China started making bronze and copper shells. It wasn't long before the Chinese made round coins out of metal. ____ By 500 BC, metal coins had begun to appear in countries like Persia and Greece, and later in the Roman Empire.
About 1000 years later, leather was used as money in China, and in 806 AD, the first paper banknotes were produced by the Chinese people. ____
A. As time went by, trade between countries increased.
B. People also began collecting foreign coins as souvenirs.
C. They also used tiny shells as money for buying and selling.
D. It was still many years before paper money appeared in Europe.
E. However, as economies developed, such exchanges became impractical.
F. During that time, for example, buying a chicken might cost several potatoes.
G. The very first coins often had holes in them so that people could tie them together.
