21.---what do you think of ________ concert last night? ---no doubt it was _______ great success. a .a; the b. the; a c. the ; 不填 d. a; 不填 22.---do you mind if i keep pets in this building? ---______. a. i’d rather you didn’t, actually b. of course not. it’s not allowed here. c. great. i love you. d. no, you can’t