27. Our government has done a lot to solve the shortage of oil, but it may take some time ______ we have enough.

　 A. afterB. since C. before D. unless

26. Franklin’s being good at learning from observations and experiences ______ greatly to his success in political life.

　　 A. owedB. addictedC. contributedD. related

25. Everyone has periods in their lives ______ everything seems very hard.

　 A. whereB. which　 　　　 C. when　 D. that

24. - Ring me at six tomorrow morning, will you?

- Why that early? I ______ .

　 A. will be sleeping　　 B. have sleptC. have been sleeping D. will sleep

23. - ______?

- Nothing serious, but a bit tired.

　 A. Anything the matter with youB. Is that all　

C. Anything elseD. What’s this

22. - Hello! May Flower Hotel. Can I help you?

- Do you have a room ______ for this weekend?

A. accessible　　　　　 B. present　　　 　　　　　　 C.　　 absentD. available