Passage Three 　　Questions 17 to 20 are based on the passage you have just heard. 　　17. A) The causes are obvious. 　　B) The causes are very complicated. 　　C) The causes are familiar. 　　D) The causes are not well understood.(B) 　　18. A) Regular driver training. 　　B) Improved highway design. 　　C) Stricter traffic regulations. 　　D) Better public transportation.(B) 　　19. A) Highway crime. 　　B) Poor traffic control. 　　C) Confusing road signs. 　　D) Drivers errors.(D) 　　20. A) Designing better cars. 　　B) Building more highways. 　　C) Increasing peoples awareness of traffic problems. 　　D) Enhancing drivers sense of responsibility.(A) 　 　Part I 1. B 2. C 3. B 4. C 5. D 6. A 7. B 8. A 9. D 10. C