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

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。