Not until I began to work how much time I had wasted.　 A. didn't I realize　 　B. did I re

问题补充：

Not until I began to work how much time I had wasted.

A. didn I realize

B. did I realize

C. I didn realize

D. I realize

答案：

A. didn I realize

(答案→)B. did I realize

C. I didn 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。