GWD-TN-1-41 疑问

ddream777

这一题有些疑问，答案说事C. 就算是没错，但是感觉上 E 也可以啊？难道是 well established as early as 18th century 是 fragment ?

Leaching, the recovery of copper from the drainage water of mines, as a method of the extraction of minerals, it was well established as early as the eighteenth century, but until about 25 years ago miners did not realize that bacteria take an active part in the process.

A.    as a method of the extraction of minerals, it was well established

B.    as a method of the extraction of minerals well established

C.    was a well-established method of mineral extraction

D.    was a well-established method of extracting mineral that was

E.     had been a method of mineral extraction, well established

ywxkdxh

对于E项，网上众说纷纭···我觉得had been最有可能成为这一项的绝对性错误。可以看看国外的一个解释http://e-gmat.com/blogs/?p=389
“Choice E – Verb error:  This choice states uses past perfect tense for the verb – had been.  This changes the intended meaning of the sentence.  This sentence now implies that leaching is no longer a method of mineral extraction.  In the light of this information, what follows does not make sense.  Since this is no longer a method of mineral extraction, the fact miners realized its working 25 years back becomes invalid.  Thus, because this sentences uses past perfect tense as shown, it distorts the intended meaning of the sentence.”
不过这个解释给我的感觉是，过去完成时是指“由过去的某一时刻开始，一直延续到过去另一时间的动作或状态，并在这个时间点截止”。但是曼哈顿只是说在过去的过去发生，木有表明用过去完成时的动作一定是在过去的一个时间点截止。所以我就迷惘了···

ddream777

I think the explanation from e-gmat.com makes sense. Thanks!