问题补充：
I really don’t know I kept the secret papers.
A. where was it
B. it was where that
C. where it was that
D. where was it that
答案：
A. where was it
B. it was where that
(答案→)C. where it was that
D. where was it that
解析：考察宾语从句和强调句的结合。根据句子结构可知，该句为宾语从句和强调句的结合。
宾语从句中要使用陈述语气，
