II、单项选择（共15小题；每小题1分，满分15分）
21. Once a decision has been made, all of us should _______ it.
A. direct to B. stick to C. lead to D. refer to
22. ---Do you mind if I open the window ? ---_______. I feel a bit cold.
A. Of course not B. I’d rather you didn’t
C. Go ahead D. Why not?
