Liu Fang is a company CEO now but she as a teacher in a middle school for three years.A.

问题补充：

Liu Fang is a company CEO now, but she as a teacher in a middle school for three years.

A. worked

B. has worked

C. works

D. had worked

答案：

(答案→)A. worked

B. has worked

C. works

D. had worked

解析：

试题分析:考查动词时态。从上文可知她在学校工作是过去的事情，和现在无关，故用一般过去时表示单纯发生在过去的动作或存在的状态，答案选A。句意：刘芳现在是公司的CEO，但是她曾在一所中学当过三年教师。