紧!急!求援

XDJMs, Can y y help me to understand the following questions?

1. 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  (X)

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

For this question the answer is A but i think A missed a helping verb [did]

That flourished at the same time as [did] the civilizations  or [did]

I always have a confusion when should we add the HELPING VERB in such structure as the Same as, more ... than etc. can anyone explain it to me? much much appreicated!

That flourished at the same time as the civilizations,像本句as从句的谓语与主句的谓语 flourished 相同的情况（词，时态等），应该可以省略。

2) What was as remarkable as the development of th ecmpact disc has been the use of the new technology to revitalize in better sound than was ever before possible, some of the classic recorded performances of the pre-LP era

A) What was as remarkable as the development of th ecmpact disc

B)The thing that was as remarkable as developing the compact disc

C)NO less remarkable than the development of the cmpact disc (X)

D)Developing the compact disc has been none the less remarkable than

E) Development of the compact disc has been no les remarkable as

I want to ask why A is not right, I can not see what's wrong with choice A ????

本题在A|C之间确实有点难以抉择。我想，A的问题主要有两个方面，（1）what从句的过去时不好，联系后面的than was ever before possible中的过去时和主句的现在完成时，觉得what从句用过去时不妥。

（2）如果将此主系表结构的主语与表语对调，比较一下答案A和答案C，则会发现，A没有C简洁。

一家之言，请指正！