核心问题
It is hard for me to imagine what I would be doing today if I ____ in love, at the age of seven, with the Melinda Cox Library in my hometown. A. wouldn't have fallen B. had not fallen C. should fall D. were to fall(上海高考,02-37)
答案为 B, 但是, had not fallen 为过去完成时, 而前面的分句用的却是 would be doing。这种虚拟语气的时态关系是不对的。我认为应改为 would have done。
词典解答
上题中的虚拟语气的用法是正确的。这是一种错综时间条件句。在上面的句子里，had not fallen 表示与过去事实相反，而 would be doing 表示与现在事实相反，见 conditional sentences of mixed time。