四. 语法应用 : Model verbs.
1. Michael _______ be a policeman, for he is much too short .
    A. needn’t     B. can’t      C. should     D. may 
2.  I told Shally how to get here. But perhaps I _______ for her.
    A. had to write it out            B. must have written it out 
    C. should have written it out      D. ought to write it out