—Where did you get to know the professor over there?

—It was at the workshop           we did research together two years ago.

A．that           B．there         C．which          D．where

---Where did you get to know the professor over there?

---It was at the workshop ____ we did research together two years ago.

A. that　　　　 B. there　　 C. which　　 D. where

—Where did you get to know the professor over there?

　 —It was at the workshop ________ we did research together two years ago.

A. that　　　　　 B. there　　　　　　 C. which　　　　　　 D. where