30. ________ both sides accept the agreement will a lasting peace be established in this region.

　A. Only if　　　　 　　B. Unless　　　　　　 C. If only　　　　 D. As long as

29.________ new cure for this disease that medical experts have recently developed proves to be__________ most effective, although it can not completely kill all the viruses.

　A. A; a　　　　　　 B. The; /　　　　　　 C. /; the　　　　　 D.A; the

28.The machine has been used much too long. _______ it doesn’t work well sometimes.

A. It’s no wonder that　 B. There’s no doubt if C. It’s unluckily　 　　　 　D. That’s because

27.Only through hard work and patience __________ his childhood dream.

　A. he realized　　　　 B. did he realize　　 　　 C. realized he　　　 D. realize did he

26. I’ve heard that our boss is to arrange me for a trade talk with another company, _______ I

can’t go picnicking with you on Sunday.

　A. in this case　　　　 B. in that case　　　 　 C. in which case　　 D. in case

25. Those who are of great determination are ________ to make great achievements.

　 A. maybe　　　　　 B. likely　　　　　　 C. probably　　　　 D. possible

24. While writing a letter, _________.

　A. The doorbell rang　　　　　　　　　　 　 B. The doorbell rings

C. I heard the doorbell ring　　　　　　　 　 D. I heard the doorbell rings

23.We need help badly, so ________ the interview with the applicants as quickly as possible.

　A. realize　　　　　 B. arrange　　　　　 　　 C. manage　　　　 D. hold　

22.Samuel Clemens, _________ Mark Twain, became a famous American writer.

　A. known for　　　 B. is known for　　　 　 C. known as　　　　 D. is known as

21. ________, the three countries found themselves ________ peacefully instead of by war.

　A. Much to their surprise; united　　　　　 　 B. To their great surprises; united

　C. Much to their surprise; uniting　　　　 　　 D. To their great surprise; uniting