问题
选择题
I failed in the final examination last term and only then _______ the importance of studies.
A.I realized
B.I had realized
C.had I realized
D.did I realize
答案
D
此题考查倒装结构。only+副词、介词短语、状语从句并和这些成分一起提前时,句子要用部分倒装;而且我的醒悟不会在考试以前,所以不能选C项。