21.—Won’t you join us in playing tennis?
—_______. I’d rather watch it than play it.
A. Why not? B. No, thanks. C. Go ahead. D. Have fun.
22. The volunteers are doing ______ important work，they share ________ common goal —— to help people in need.
A. a; a B. a; the C. 不填；the D. 不填；a
