—Mr. Wang is in Nanjing for a trip.—Oh really? When he the trip?A. does; startB. will;

问题补充：

—Mr. Wang is in Nanjing for a trip.

—Oh, really? When he the trip?

A. does; start

B. will; start

C. did; start

D. is; starting

答案：

A. does; start

B. will; start

(答案→)C. did; start

D. is; starting

解析：根据语境可知此句的含义是什么时候开始旅行的？描述的过去事情，故用一般过去时。因有when引导，故是特殊疑问句，其基本构成是特殊疑问词+一般疑问句？