21. — Really? Who will give __________ lecture next Saturday?
— Mr. Wang, __________ professor from Nanjing University.
A. the; 不填 B. the; a C. a; the D. a; a
22. — What about Mr. Brown’s speech?
— I understood most of what he said, but not __________ word.
A. any B. each C. every D. one
