Unfortunately, when I dropped in, Professor Smith , so we only had time for a few words.
A. has just left
B. had just left
C. just left
D. was just leaving
网友回答
A. has just left
B. had just left
C. just left
(答案→)D. was just leaving
解析：从“我们只谈了几句话”可知，当我们去拜访时，Professor Smith“正要”离开了，D是过去进行时表示过去将来意义。