听力原文：Narrator Listen to part of a talk in an economy class. Professor Many businesses, such as department stores, restaurants, hotels, and airline companies, use a credit system for selling their products. In a credit system the seller agrees to sell something to the buyer without immediately receiving cash. The buyer receives the goods or services immediately and promises to pay for them later. This 'buy-now, pay-later' credit system is quite old. People have been buying things on credit for centuries. However, nowadays people use credit cards. There are two types of credit cards. One type is issued directly by a store to a customer. Many large department stores issue credit cards to their customers. The store credit card can be used to make purchases only at a particular store. For example, a credit card from Swans Department Store can be used only at Swans Department Store. The other kind of credit card is issued by a credit company. VISA and American Express are examples of credit companies. Credit cards from credit companies can be used to buy things almost anywhere. If you have a major credit card, you can buy airplane tickets, stay at hotels, and eat at restaurants with it. Most large credit companies are connected to large banks. So if you want a credit card from a credit company, you generally have to make an application at a bank. After an applicant receives a credit card, he or she can make purchases using the card. The credit company sends the customer a statement of purchases at the end of each month. Generally, the customer has to pay 25 to 50 percent of their credit bill every month. The customer pays directly to the credit company. And the credit company pays directly to the store, hotel, or restaurant. There are some advantages and disadvantages to using credit cards. The biggest advantage for the consumer is expressed by the phrase 'buy-now, pay-later'. This means that the consumer can purchase what she wants when she wants it. There is no need to save up money in advance. Another advantage of having a credit card is that it protects the owner. If a credit card is lost or stolen, the owner only has to call the credit company and the credit company will stop the credit card number. No one else can use it. So the owner doesnt have to worry about losing the card. A third advantage of the credit card system is that the consumer receives a record of her purchases. Every month the credit customer receives a bill. The bill has a list of all purchases from that month. This makes it easier to remember when and where purchases are made. And the fourth advantage is that a credit card can be used when something unexpected happens. Many kinds of professional people—plumbers, taxi drivers, doctors, and dentists—will accept credit cards in an emergency. This is very important if you dont have any cash with you. Using credit cards has one major disadvantage though. The main disadvantage is that consumers tend to overspend; they spend more than they make. If a consumer buys a lot of things on credit, she has to make large payments each month. Sometimes, it becomes impossible to keep up with the payments. The consumers life becomes more and more difficult. If the consumer cant make her payments, her credit card will be taken away. It will be very difficult for her to get another card in the future. So we can see that a credit buying system has some advantages and some disadvantages. On the one hand, it gives people some buying freedom; on the other hand, it tends to encourage overspending. Now get ready to answer the questions. You may use your notes to help you answer. 17. What is the talk mainly about? 18. Why does the professor mention VISA and American Express? 19. Which expression is NOT true according to the professor? 20. How does the professor clarify the advantages of using credit cards? Listen again to part of the lecture. Then answer the question. Professor Using credit cards has one major disadvantage though. The main disadvantage is that consumers tend to overspend; they spend more than they make. If a consumer buys a lot of things on credit, she has to make large payments each month. Sometimes, it becomes impossible to keep up with the payments. The consumers life becomes more and more difficult. If the consumer cant make her payments, her credit card will be taken away. It will be very difficult for her to get another card in the future. 21. What is the professors reason for saying this? Professor It will be very difficult for her to get another card in the future? 22. Whats the professors general attitude towards using credit cards?Narrator Listen to part of talk in an economy class. Now get ready to answer the questions. You may use your notes to help you answer. What is the talk mainly about?