We didn’t start our discussion everybody arrived.A. sinceB. ifC. whileD. until

问题补充：

We didn’t start our discussion everybody arrived.

A. since

B. if

C. while

D. until

答案：

A. since

B. if

C. while

(答案→)D. until

解析：这里考核not…until…(直到……才……)的复合句内容，根据题干的意思理解，学生应该会做。