单选题 I would have finished my paper if it was at all possible, but I was fully occupied the whole of last week.
A. had it been B. were it
C. it had been D. it were

【正确答案】 A

【答案解析】[解析] 结构应用
本句考察的是虚拟语气的应用：因本句表达得是与过去事实相反，主句用的是would have finished，那么if从句应用had been done句式；如将条件从句中的讧省略时，had需与主语倒装；因此A为答案。