I failed in the job interview and only then the importance of learning English well.
A. I realized
B. I had realized
C. did I realize
D. had I realized
网友回答
A. I realized
B. I had realized
(答案→)C. did I realize
D. had I realized
解析：考查only的倒装句；only的倒装句有两个条件：only放在句首；且强调状语；在这种情况下使用部分倒装句。本题only放在句首，强调的是时间状语then，故使用部分倒装的形式。句意我没有通过面试，直到那时我才意识到学好英语的重要性。故C正确。