7. —Does Liu Hui serve in the army? —No, but he in the army for three years. A. servedB. has servedC. is servingD. would serve用过去完成时 是一般过去式?

7. —Does Liu Hui serve in the army? —No, but he in the army for three years. A. servedB. has servedC. is servingD. would serve用过去完成时 是一般过去式?
7. —Does Liu Hui serve in the army?
—No, but he in the army for three years.
A. servedB. has served
C. is servingD. would serve
用过去完成时 是一般过去式?

7. —Does Liu Hui serve in the army? —No, but he in the army for three years. A. servedB. has servedC. is servingD. would serve用过去完成时 是一般过去式?
A.served
这里面只能选A,sever是个延续性动词,后面可以跟一段时间
按理说也可以用过去完成时的,但选项里没有

用一般过去式，代表这一动作现在已经结束了，只在过去发生。