OG80 之疑惑

80. Salt deposits and moisture
threaten to destroy the Mohenjo-Daro excavation in Pakistan, 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

不能省，否则比较对象不清。我把the same ...as...看成是个比较关系，这里是主语之间比。