The man is teaching in our school, but，believe it or not，he as a business man for 8 years.
A. worked
B. was working
C. had worked
D. has been working
网友回答
(答案→)A. worked
B. was working
C. had worked
D. has been working
解析：现在在学校教学，因此做生意人8年是一个发生在过去的动作，用过去式