In this section, you will hear a short passage. For questions 21—30, complete the notes using no more than three wards for each

In this section, you will hear a short passage. For questions 21—30, complete the notes using no more than three words for each blank. The passage will be read only once. Remember to write the answers on the answer sheet.
    Today, currency is a mixture of coins and paper money. But it wasn’t always that way. Before people had metal coins and paper bills, they used a lot of unusual things for money. In one part of the world, for example, people used sharks’ teeth for money. In some places, brightly colored feathers and rare seashells were money. People in one area even used the hair from elephants’ tails for money.
    No one knows for sure when people started using metal coins for money. The oldest coins are over 2,500 years old, so we know that people used coins a very long time ago. At first, people used precious metals, such as gold and silver, to make coins. They stamped the shape of a person or animal on each coin to indicate its value.
    In the 13th century, people in China used iron coins for their currency. These coins weren’t worth very much, and people had to use many of them to buy things. Because it was inconvenient to carry so many coins, the government started making paper receipts. People took these receipts to banks and traded them for coins. This was the first example of paper money.
    Today, most countries use a mixture of coins and paper bills for their currency. In the United States, the paper bills are all the same size and color. For example, the $ 1 bill is the same size and color as the $100 bill. In many other countries, the bills have different sizes and colors. The smaller bills are worth less money. This makes it easier for people to tell the value of their money. In 2002, twelve European countries started using a completely new currency. It’s called " the euro". Many Europeans miss their old currencies, but now it’s easier to move money from one country to another.
    Here are a few more fascinating facts about the history of money.
    Feathers were the lightest money ever used. People on the Pacific island of Santa Cruz used them. Stones were the heaviest money ever used. People on the Pacific island of Yap used them. Some weighed over 500 pounds.
    The smallest money ever used was in Greece. The coins were made of metal, but they were smaller than an apple seed.