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
网友回答
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的倒装有两个条件，首先only放在句首，其次后面要强调状语。本句两个条件都满足了。Only放在句首强调了条件状语从句，所以后面使用倒装句。