问题补充：
Do you know this time yesterday?
A. what she is cooking
B. what is she cooking
C. what she was cooking
D. what was she cooking
答案：
A. what she is cooking
B. what is she cooking
(答案→)C. what she was cooking
D. what was she cooking
解析：考查宾语从句。句意“你知道昨天这个时候，......”，宾语从句用陈述句语序，排除B、D；this time yesterday提示用过去进行时。故选C。
