21．Miss Li ________ as a biology teacher for fifteen years in our school, and now she is Party secretary of our city.

A. works                            B. worked                         C. had worked                 D. has worked

Miss Li ________ as a biology teacher for fifteen years in our school, and now she is Party secretary of our city.

A. works　　　　　 B. worked　　　 C. had worked　 D. has worked

Miss Li ________ as a biology teacher for fifteen years in our school, and now she is Party secretary of our city.

1. A.
   works
2. B.
   worked
3. C.
   had worked
4. D.
   has worked

.

Miss Li ________ as a biology teacher for fifteen years in our school, and now she is Party secretary of our city.

A. works B. worked      C. had worked       D. has worked

.Miss Li ________ as a biology teacher for fifteen years in our school, and now she is Party secretary of our city.

A. works      B. worked      C. had worked    D. has worked