Question

He failed the midterm examination and only then________how much time he had wasted.

A. he realized　　　　　　　 B. did he realize

C. he had realized　　　　　 D. had he realized

 

Answer 1

B

本题考查动词的时态和倒装句的用法。根据语法要求only引导状语位于句首时，需要使用倒装句结构。而该状语only then表明了动作发生在过去。