21. Finally, he was cured ___________ cholera? 

A. of                   B. with                 C. to                       D. off

22. As nobody here knows what is wrong with the machine, we must send for an engineer to _____ the problem.

A. handle                B. raise                C. face                 D. present

23. As winter _____,weather became cold.

A. approaches                B. approaching              C. to approach                  D. approached