Good friends as we are, I still find her difficult to understand ________.

1. A.
   at one time
2. B.
   at a time
3. C.
   at times
4. D.
   at the time

 Good friends as we are, I still find her difficult to understand ________.

      A. at one time B. at a time     C. at times    D. at the time

Good friends as we are, I still find her difficult to understand ________.

  A. at times                B. at a time                   C. at one time               D. at the time