21. ________at all ________we did the right thing.
A. It is no doubt; that
B. There is no doubt; that
C. It is no doubt; whether
D. There is no doubt; whether
22. My sister met him at Ningbo Grand Theatre yesterday afternoon, so he________ your lecture.
A. couldn’t attend
B. mustn’t have attended
C. shouldn’t attend
D. couldn’t have attended
