for the captain ,the ship would have sunk with all on board .
AHadn’t it been
B. Had it been not
C. Not had it been
D. Had it not been
网友回答
A. Hadn’t it been
B. Had it been not
C. Not had it been
(答案→)D. Had it not been
解析：这相当于if引起的条件状语从句的虚拟语气的句子，把Had提到前面，句子用倒装语序。