He was medical student before he turned engineer. A. a; an B. the; the C. a; / D

He was ______ medical student before he turned _______ engineer.

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

试题答案

C

解析:

第一空表示一的概念，后一空前用了连系动词turn，所以名词前不用冠词。