(A)单项填空从A、B、C、D四个选项中，选出可以填入空白处的最佳选项。
21. _______ enjoyable music programme on Channel 3!
A. How B. How an C. What D. What an
22. ---What are the police doing there?
---They are _______ the building. A robber ran into it just now.
A. finding B. searching for C. searching D. looking for
