I want to know is I can master English in the shortest possible time.A. What; howB. How

问题补充：

I want to know is I can master English in the shortest possible time.

A. What; how

B. How; what

C. Which; what

D. What; what

答案：

(答案→)A. What; how

B. How; what

C. Which; what

D. What; what

解析：考查名词性从句。第一格是名词性从句中缺少宾语，故用what；第二格，表语从句缺引导词，由于从句中不缺少主要成分，所以不能用what，根据意思，我想知道的是我怎么能够在短时间内掌握英语。