You must have read about Mark Twain long ago ?A. mustn't youB. haven't youC. didn't youD.

问题补充：

You must have read about Mark Twain long ago, ?

A. mustn you

B. haven you

C. didn you

D. needn you

答案：

A. mustn you

B. haven you

(答案→)C. didn you

D. needn you

解析：考查反义疑问句。句中must have done 表示对过去的肯定推测，而且有明显的时间状语long ago。做反义疑问句时用助动词did，所以答案选C。