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（A）

(E) flourishing at the same time as those were

在这里，为何不能用 分词，不好意思，这样的问题好像比较简单

614, og-080, sec08-14

Choice A, the best answer, uses the simple past tense flourished to describe civilizations existing simultaneously in the past. Choice B wrongly uses the past perfect had flourished; past perfect tense indicates action that was completed prior to some other event described in the simple past tense: for example, “Mayan civilization had ceased to exist by the time Europeans first reached the Americas.” Choice C lacks as after time. In choices C, D, and E, the plural pronoun those has no plural noun to which it can refer. In C, had signals the incorrect past perfect; did in D and were in E are awkward and unnecessary. D and E also incorrectly use the present participle flourishing where that flourished is needed