21. I smoke out of _____ habit, not for _____ pleasure; for I have been in the habit for twenty years.

A. a; the       B. the; a               C. /; the      D. /; /

22. Were it not for the snowy weather, we _____all right.

A. would be    B. would have been      C. were       D. may be

23. Jenny______ have kept her word .I wonder why she changed her mind.
A. must          B. should              C. need                     D. would