is to be done isto carry it out smoothly since the decision has been made. A. What; howB.

问题补充：

is to be done isto carry it out smoothly since the decision has been made.

A. What; how

B. Where; how

C. When; what

D. Where; what

答案：

A. What; how

B. Where; how

C. When; what

D. Where; what

解析：选A。考查主语从句。句意: 既然已经做出了决定, 要做的就是如何去顺利完成。根据句意“需要做的……”用what; 语境“如何顺利完成……”用how, 故答案为A。