It is human nature to think back to a golden age one’s country was strong and respected.A

问题补充：

It is human nature to think back to a golden age one’s country was strong and respected.

A. if

B. when

C. while

D. after

答案：

A. if

(答案→)B. when

C. while

D. after

解析： 此句是对定语从句的考查，先行词为表示时间的词，且在从句中作状语，所以选when