Not until I began to work how much time I had wasted.
A. didn't I realize
B. did I realize
C. I didn't realize
D. I realize
网友回答
A. didn't I realize
(答案→)B. did I realize
C. I didn't realize
D. I realize
解析：句意，直到我开始工作，我才意识到自己已经浪费了很多时间。not until，引导的时间状语从句置于句首，从句要用陈述语序，主句要用倒装语序，故选B。