C. playingD. B and C are correct21 4, Are you really interested………..English subject?22A,inB, onC, at.D, for23 5, My father always ……….to work on time.24A, goB, goesC, to goD,going25 6. Mary enjoys………….in the river with her friends.26A, swimB, swimmingC, to swimD, swam27III,Dùng từ gợi ý để viết thàn[r]