请教：刘振民语法改错E9-30

Salt deposits and moisture threaten to destroy the Mohenjo-Karo excavation in Pakisstan, the site of an ancient civilization that flourished at the same time as the civilizations in the Nile delta and the river valleys of the Tigris and Euphrates.

A. that flourished at the same time as the civilizations

B.that had flourished at the same time as had the civilizations

C.that flourished at the same time those had

D.flourishing at the same time as those did

E.flourishing at the same time as those were

正确答案是A，的确B，C，D，E都有明显错误，可是我觉得A好像也有问题。

请教各位大牛，the same time as之后为什么没有补出谓语动词？

请回帖或MSN：zaecho[在] yahoo.com

thanks!

获益匪浅。。。