I was about to go to bed one of my old classmates made a call to me.A. thatB. asC. whileD

问题补充：

I was about to go to bed one of my old classmates made a call to me.

A. that

B. as

C. while

D. when

答案：

A. that

B. as

C. while

(答案→)D. when

解析：考查固定结构。Be about to do sth when…正要做某事在这时….（意料之外的事情发生）；句意：我正要上床睡觉，在这时我的一个老同学打了个电话给我。