Only when I left my parents for Italy how much I loved them.A. I realized B. I had realiz

问题补充：

Only when I left my parents for Italy how much I loved them.

A. I realized

B. I had realized

C. had I realized

D. did I realize

答案：

A. I realized

B. I had realized

C. had I realized

(答案→)D. did I realize

解析：考查倒装句。Only +状语/状语从句提前，主谓应用部分倒装。故排除A和B，有根据前面的left，可知本句应是过去时。