The climbers succeeded in climbing to the top of the mountains, and they owed their success to the preparations they .
A. make
B. had made
C. made
D. have made
网友回答
A. make
(答案→)B. had made
C. made
D. have made
解析：句意：登山者们最终设法登上了山顶，他们把这归功于先前他们所做的准 备。根据 succeeded和 owed 可知做准备是过去的过去的动作，此处应用过去完成时表示“过去的过去” 。所以选B。