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

指环量规中，（）是用于测量手指确定所需戒指圈口尺寸的标准圈，（）是用于成品戒指圈口测量的。