I was just about to leave the telephone rang.A. whileB. asC. beforeD. when

问题补充：

I was just about to leave the telephone rang.

A. while

B. as

C. before

D. when

答案：

A. while

B. as

C. before

(答案→)D. when

解析：考查固定搭配：be about to do when…刚要做…这时，句意是：我刚要离开这时电话响了。选D。