听对话,回答问题。 1. What happened to Mela two years ago? A. He met Kam. B. He had an accident. C. He lost his best friend. 2. How old is Mela? A. He is 15 years old. B. He is 13 years old. C. He is 9 years old. 3. How long did it take Mela to get to the North Pole (北极)? A. 20 days. B. 23 days. C. 21 days. 4. How does Mela walk after he lost a leg? A. With the help of a man-made leg. B. With the help of his mother. C. With the help of a wheel chair.