单项选择题
Questions 14 to 17 are based on the following passage. At the end of the passage, you will be given 20 seconds to answer the questions. Now, listen to the passage.
When did Ben first become interested in Mongolia（）
A．When he grew up. B．When he learned Mongolian. C．When he returned home. D．When he was nine years old.
单项选择题 Which of the following is NOT mentioned about the single-lens reflex? （）
单项选择题 Which of the following details about the front of the house is CORRECT?（）
单项选择题 What are they mainly talking about in the conversation（）
