Question

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

1. A.
   didn't I realize
2. B.
   did I realize
3. C.
   I didn't realize
4. D.
   I realize

Answer 1

B
这是一个倒装句型。带有否定意义的词或短语放在句首，语序需要部分倒装。常见的词语有not，never，seldom，scarcely，barely，little，at no time，not only，not once，under，no condition，hardly…when，no sooner…than等。这里not until是否定副词，因此选B。