We were about to start out our friends called us up from Shanghai.A. whenB. whileC. untilD

问题补充：

We were about to start out our friends called us up from Shanghai.

A. when

B. while

C. until

D. before

答案：

(答案→)A. when

B. while

C. until

D. before

解析：考查连词：be about to do常和when连用，表示“刚要做…这时…”,句意：我们刚要出发，这时朋友从上海打电话给我们。选A。