It was a time volunteers from all over the world visited this nursing home regularly.
A. which
B. what
C. where
D. when
网友回答
A. which
B. what
C. where
(答案→)D. when
解析：考查考查定语从句。本题定语从句的先行词是a time,后面定语从句的句子结构很完整，故使用关系副词when在句中做状语，引导定语从句。句意:这是一个全世界的志愿者都经常来的敬老院的时代。故D正确。