D. to repair

14._______ a teacher in a university, it is necessary to have at least

a master’s degree.

( A )

A. To become

B. Become

C. One becomes

D. On becoming

15.The doctor advised her _______ enough rest before going back to

work.

( B )

A. get

B. to get

C. gets

D. got

16.The workers are busy _______ models for the exhibition（展览）.

( D )

A. to make

B. with making

C. being making

D. making

17.He spoke so loudly _______ be heard by all.

( C )

A. that could

B. in order

C. as to