问题补充:
Only after Helen moved to Australia how important she was to me .
A. I had realized
B. had I realized
C. I did realize
D. did I realize
答案:
A. I had realized
B. had I realized
C. I did realize
(答案→)D. did I realize
解析:考查倒装,因为only位于句首,所以用倒装,所以选D