21. —— Did you have fun at the ball last night?
—— ______! I’ve never had a more wonderful time all my life.
A. You bet B. No problem C. Don’t mention it D. That’s right
22. —— Why do you look so worried?
—— My computer broke down and my essay ______ unfinished since.
A. had left B. has left C. was left D. has been left
