Notuntiloneofmyclassmateshadpattedmeontheshoulder

問題詳情：

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

知識點：倒裝與省略

題型：選擇題