20. But for the help of my teacher, I 　　　the first prize in the Competition.

　　 A. would not have won　 B. had not won　 C. would have won　　　 D. have won

19. So sudden 　　　　　that the enemy 　　　　　no time to escape.

　　 A. did the attack; had 　　　　　　　　　　　　　　　　　 B. was the attack; had had

　　 C. was the attack; had 　　　　　　　　　　　　　　　　　 D. did the attack; had had

18.　　 twice, the postman refused to deliver our letters unless we chained our dog.

　　 A. Being bitten　　　　　　 B. Bitten　　　　　　　　　　 C. Having bitten　　　　　 D. To be bitten

17. The news came as quite a shock to us, but he seemed to be_________ surprised.

A. simply　　　　 　 　B. entirely　　　 　　C. absolutely　　 　　D. hardly