21. ---Mrs. Black, this is our language lab. Would you like to go in and have a look?
--- Ok.._______ .
A. Help yourself B. This way, please C. Follow me D. After you
22. They only say such unkind things about you out of ____ envy, because you are ____ success as a writer.
A. the; a B. the; / C. /; a D. /;
23. Nowadays some hospitals refer to patients ____ name, not by case number.
A. of B. as C. by D. with
