Notuntiloneofmyclassmateshadpattedmeontheshoulder

问题详情：

Not until one of my classmates had patted me on the shoulder ___________ that I should make an apology to Mr. Smith.

   A. had I realized            B. I had realized             C. did I realize       D. I realized

【回答】

C

知识点：倒装与省略

题型：选择题