Not until Mr. Smith came to China what kind of a country she is from.A. Didn’t he know 　B

问题补充：

Not until Mr. Smith came to China what kind of a country she is from.

A. Didn’t he know

B. Had he known

C. Hadn’t he known

D. Did he know

答案：

A. Didn’t he know

B. Had he known

C. Hadn’t he known

(答案→)D. Did he know

解析：not until 在句首主句要部分倒装。