—You seem to have known Dr. Ken for a long time.

     —That’s true. ________ he joined our club years ago.

A. Since          B.Until      C. When           D. If

---You seem to have known Dr. Ken for a long time.
---That’s true. ______ he joined our club years ago.

1. A.
   Since
2. B.
   Until
3. C.
   When
4. D.
   If

—You seem to have known Dr. Ken for a long time.

     —That’s true. ________ he joined our club years ago.

A. Since          B.Until      C. When           D. If

—You seem to have known Dr. Ken for a long time.
—That’s true. ________ he joined our club years ago.