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.

【正确答案】 A
【答案解析】[解析] 本句考查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if省略时,had需与主语倒装。因此A为答案。