when did he leave th classroom?he left __ you turned back to

问题描述:

when did he leave th classroom?he left __ you turned back to
——when did he leave th classroom?
——he left __ you turned back to write on the blackboard.
A.the time B.until C.the minute D.before

选C,问句的意思是,他什么时候离开教室的?按照逻辑应是当你转过身在黑板上写字之后离开的,C选项有这一刻的意思,整句翻译是他在你转过身在黑板上写字之后的那一刹那离开的.