—When did he leave the classroom?

—He left       you turned back to write on the blackboard.

A．the minute                  B．the time              C．until                   D．before

—When did he leave the classroom?

       —He left       you turned back to write on the blackboard.

       A．the minute       B．the time    C．until  D．before

28.“When did he leave the classroom?” “He left _______ you turned back to write on the blackboard.”

A. the time        B. the moment      C. until           D. since

 —When did he leave the classroom?

         —He left _____you turned back to write on the blackboard.

         A. the minute  B. the time       C. until     D. before

“When did he leave the classroom?” “He left _______ you turned back to write on the blackboard.”

A. the time     B. the moment

C. until   D. since