单项选择题

Directions: In this section, you will hear 2 passages. At the end of each passage, you will hear some questions. After you hear a question, you must choose the best answer from the four choices marked A, B, C and D. Then mark the corresponding letter on the Answer Sheet with a single line through the centre.
Passage A

Questions 21 to 25 are based on the passage you have just heard.