How are the kids spending their childhood? I can’t help recalling（回忆）that there was a time we played happily and freely in the outside.
A. that
B. which
C. when
D. 不填
网友回答
A. that
B. which
(答案→)C. when
D. 不填
解析：考查定语从句。本定语从句的先行词是a time，定语从句的结构很完整，故使用关系副词when.句意：我情不自禁地回想起那一段我们在外面开心自由玩耍的日子。故C正确。