The Russian rocket designer has died. For many years, he as an important assistant to the father of Soviet space program.
A. serves
B. was serving
C. served
D. has served
网友回答
A. serves
B. was serving
(答案→)C. served
D. has served
解析：考查时态。本题使用一般过去时，描述过去所发生的动作，本句中没有反应出对现在的影响也没有延续到现在，故不要使用现在完成时。句意：俄罗斯的火箭设计师去世了。很多年来，他都充当俄罗斯的太空计划之父的角色。故C正确。