21. He ____________ his old car for a new one as soon as he had won the prize.

A. replaced        B. converted        C. exchanged        D. interchanged

22. He is a very _______________ character; he is never relaxed with strangers.

A. serf-confident    B. self-conscious     C. self-evident       D. self-serving

23. You’ll find that the community has _____________ great changes since you were here last time.

A. submitted       B. sustained         C. perceived        D. undergone

24. You don’t have to ___________ yourself. I think you did the right thing putting your mother in a nursing home.

A. justify         B. hinder           C. indulge          D. appoint

25. If prisoners behave well they are allowed the ___________ of visiting their families at the weekend.

A. equality        B. security         C. privilege         D. prestige