21. The biggest whale is___ blue whale, which grows to be about 30 meters long—the height of ___ 9-storey building.
A. the; the          B. a; a           C. a; the        D. the; a
22. It’s beyond our imagination that Jim, who tops the class in English, ______ have difficulty translating the simple sentence.
A. shall         B. might               C. should                  D. must