—The accident might not have happened, had we been more careful.

—But we ______.

        A. weren’t           B. didn’t        C. hadn’t     D. don’t 

 ―The accident might not have happened, had we been more careful.     

 ―But we ______.

 ―The accident might not have happened, had we been more careful.     

―But we ______.

        A. weren’t                  B. didn’t                       C. hadn’t                      D. don’t 

--- The accident might not have happened , had we been more careful .
--- But we _______

1. A.
   didn’t
2. B.
   hadn’t
3. C.
   weren’t
4. D.
   don’t

--- The accident might not have happened , had we been more careful .

   --- But we _______.

 A. didn’t   B. hadn’t   C. weren’t   D. don’t