21. They will give the prize money to _______ pays enough attention to the protection of wild life.

A. who                       B. anyone                   C. whomever               D. whoever

22. The pollution in this city will ________ serious for quite a few years.

    A. keep                      B. last                        C. remain                    D. continue

23. He became an actor at a very young age but it was nearly 20 years ______ he became famous.

    A. until                      B. when                     C. before                   D. that