听力原文：A:Good afternoon. This is American airlines. Can I help you? B:Good afternoon. I'd like to cancel my reservation on flight 18 to London on July 10th, the day after tomorrow. A:May I know your full name, please? B:My name is William Cotton. A: Just a moment, please. Thank you for waiting. I've canceled your reservation. Shall I make another reservation for you? B:Yes, please. I'd like to make a reservation to Beijing on July 11th. A:Hold on, please. Let me check it for you. I am sorry but our flights are fully booked that day. B: Oh, then when does the next available flight leave? A:The next available flight leaves at 8am, July 12th. Shall I reserve you a seat? B:Yes, please. ADo you prefer first class or economy class? B:I'd like economy class, please. A: And a window seat or an aisle seat? B:A window seat, please. How much is it, please? A: 1450 Yuan. Mr. Cotton, you can get your ticket at any of our offices with your ID card. Thank you for calling us. B: Thank you very much. A:You are welcome. Questions: 17. What is the date today according to the talk? 18. Why does Mr. Cotton call? 19. According to the talk, which of the following is true? 20. Which of the following can be inferred from the talk? (17)