短文理解 听力原文： In the United States, even if you decide that you do not want to borrow in order to go on vacation, it is still a good idea for you to have several major credit cards. These provide positive identification when renting an automobile and can be used for the deposit. The credit card receipts will serve as an accurate record of all hotel, plane, train, and restaurant expenses. The use of credit cards avoids the necessity of carrying large amount of cash, purchasing large amounts of traveler's cheeks and keeping track of them, or attempting to use personal checks in places other than your own locality. Many major credit cards provide an instant cash service in case you run out of money. American Express, for example, has set up machines in major airports in which you can purchase traveler's checks using your American Express card. 21. The credit card receipts will serve as accurate record for all but which of the following choices? 22.Which of the following is not true about the use of credit card? 23.Concerning the advantages of credit cards, which of the following is true? 24.According to the passage, which card has set up machines in major airports? (21)