—How long has your brother in the army ?—About five years.A. taken partB. joinedC. served

问题补充：

—How long has your brother in the army ?

—About five years.

A. taken part

B. joined

C. served

D. attended

答案：

A. taken part

B. joined

(答案→)C. served

D. attended

解析：how long 与延续性动词连用，在四个选项中，只有C是延续性动词，故选C