The country life he was used togreatly since the opening policy.A. changedB. has changedC.

问题补充：

The country life he was used togreatly since the opening policy.

A. changed

B. has changed

C. changing

D. having changed

答案：

A. changed

(答案→)B. has changed

C. changing

D. having changed

解析：此题考查考生对句子结构的分析理解能力。此题中he was used to为定语从句，对the country life进行修饰，所要选的内容应为句子的谓语动词，故排除C、D，而since通常用于现在完成时态。故选答案为B。