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题库 / Prep2008E2-SC-196
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.
as a method of the extraction of minerals, it was well established
as a method of the extraction of minerals well established
was a well-established method of mineral extraction
was a well-established method of extracting mineral that was
had been a method of mineral extraction, well established
请看讲解视频
Ron说，E错在两点，第一：时态不对，过去完成时表示leaching是过去的办法，现在不用了，但句中并没有表述这种意识； 第二，well established不应该作为非必要修饰语，个人理解从这个句意出发，前半句说这个方法好，后半句说发现这个方法的缺点，well established作为非必要修饰语，就削弱了整个句子的转折意味。
这边cd的区别是名词和ing的区别吗，是不是因为被建立了说明他是一个有时间截点的动作，所以选名词形式？？？
对，做某种事情的方法，一定隐含着这件事至少已经被完成一次，所以用名词形式
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FYI https://www.manhattanprep.com/gmat/forums/leaching-the-recovery-of-copper-t11771.html
E：inappropriate tense.
if the past perfect is used to describe a state or description of something (as opposed to an action verb), it should generally be used to describe a state/description that is no longer the case. since leaching is presumably still an extraction method (this is not the sort of thing that is subject to change), the past perfect is inappropriate.
居然错选了a。。。a有两个主语啊。。。
had been时态错，意思是已不再是method了，与原文意思矛盾
method of 后面能用一个名词表示的动词就不要用动名词形式
啦啦啦
E除了时态错误，well established修饰有问题吗？
修饰不清，可以修饰extraction也可以是method
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E选项had been的时态有问题吗？
对啦，逻辑论元核心词