11. Writing  ____________ her happy

        a. letter makes            b. letters makes           c. letter make                 d. letters make

12. None of the money robbed from the banks last year ____________ yet.

        a. has been found       b. have been found    c. has found                  d. have found

13. My father and mother ____________ for the same company.

        a. works                      b. work                       c. is working                 d. has worked

14. The elderly ____________ this kind of music, but the young ____________.

        a. don’t like / does      b. doesn’t like / does      c. don’t like / do        d. doesn’t like / do