21. — I’m sorry I didn’t make it to your party last night.
— _________. I know you are busy these days.
A. That’s all right. B. No kidding.
C. Of course. D. Don’t mention it.
22 —Li Mei has _____ good command of English.
—So she does. She plays _____ very important part in our team.
A. / ; a B. a ; a C. / ; the D. a ; the
