Occasions are quite rare I have time to spend a day with my kids.A. whoB. whichC. whyD. w

问题补充：

Occasions are quite rare I have time to spend a day with my kids.

A. who

B. which

C. why

D. when

答案：

A. who

B. which

C. why

(答案→)D. when

解析：句意为：“我有时间和我的孩子们度过一天的机会是很少的。”此处when引导定语从句，修饰occasions, 定语从句中不缺主宾表，缺少的是时间状语，而且这里为分隔式定语从句。故选D。