When the last prize had been awarded everybody cleared off.
A. and
B. so
C. or
D. 不 填
网友回答
(答案→)A. and
B. so
C. or
D. 不 填
解析：句首 when 引导的是一个时间状语从句，它暗示整个句子为复合句；而so, and, or 为并列连词，无论选哪一个，都表明整个句子为并列句，从而导致前后矛盾，所以A、B、C均不能选择。此题正确答案选D，everybody cleared off 为整个复合句的主句