----Are you a teacher?--No but I in Harbin No. 3 High School for 3 years.Ahad taug

问题补充：

----Are you a teacher?

----No, but I in Harbin No. 3 High School for 3 years.

Ahad taught

B. has taught

C. teach

D. taught

答案：

A. had taught

B. has taught

C. teach

(答案→)D. taught

解析：句意：--你是老师吗？--不，但是我在哈尔滨三中工作了五年。根据回答“我现在不是老师了，我在哈尔滨三中工作了五年”只是描述过去的动作（工作了五年）和现在没关系，所以用一般过去时态，选D。