21. —I have ____ splitting headache, too.
   —Yeah, you’re definitely coming down with _____ flu.
   A. a; a                    B. the; /                 C. a; the                D. the ; a 
22. When I graduated from high school , my family had a business ____ I never thought about getting a college education.
   A. so                      B. or                     C. though                     D. since