we have planned ahead might change when we put it into practice.
A. Whatever
B. Whenever
C. Whoever
D. However
网友回答
(答案→)A. Whatever
B. Whenever
C. Whoever
D. However
解析：考查主语从句：根据句意：当我们实施的时候，提前计划的事情可能会改变。用whatever引导主语从句，相当于anything that，B. Whenever无论何时，C. Whoever 凡是…人，无论谁，D. However无论怎样，选A。