A-A+
By the sixth century AD when few Europeans co
问题详情
By the sixth century AD, when few Europeans could read, the Chinese ______ paper.
A．invented
B．had invented
C．have invented
D．had been invented请帮忙给出正确答案和分析，谢谢！
参考答案
正确答案：B
解析：时态用法。句中有表示过去的时间状语“sixthcenturyAD”，而paper在此之前就已经发明了，表示“过去的过去”应该用过去完成时。
