21. It was all my ______ that my son had made such a silly but serious _______.
A. weakness; fault B. mistake; fault C. shortcoming; mistake D. fault; mistake
22. ---- _________I speak to Mr. Black, please?
---- I’m sorry he ________ come to the phone because he isn’t in.
A. Might; won’t B. Can; mustn’t C. May; can’t D. Couldn’t; shouldn’t
