请认真阅读下面各题，从题中所给的A、B、C、D四个选项中，选出最佳选项，并在答题纸上将该项涂黑。
21. ________ there is going to be a policy change _________ of those things is going to change.
A. Unless; few B. Until; few C. Unless; none D. Until; none
22. As workers and as citizens, we need to be able to think beyond our own self-interest and _________ what is right under the circumstances.
A. doing B. to do C. have done D. done
23. Jeremy, who ___________ on his food, looked up at the mention of the word cash.
A. has been concentrating B. has concentrated
C. had been concentrating D. had concentrated
24. Some people create jobs, foster excitement and basically make the system work. They see possibilities ___________ others see only problems.
A. that B. what C. which D. where
25. _____________ our foreign policy, we now have multiple threats, very few of which involve the traditional battles of the past.
