请教GWD1-41

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.

改选B啦。

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.

1. as a method of the extraction of minerals, it was well established
   －it 多余。
   
2. as a method of the extraction of minerals well established
   
3. was a well-established method of mineral extraction
   与as early as the eighteenth century无法连接。
   
4. was a well-established method of extracting mineral that was
   －that was引导的定语从句修饰对象不明，且that was多余。
   
5. had been a method of mineral extraction, well established
   －完成式分词短语不可做定语修饰名词。

刚刚查了字典，establish只是及物动词，应该要加宾语的，那么B中的用法是错的？

到底选什么？为什么？！！！

LES一定是把establish当作谓语了，但是我觉得当作谓语不合适的，确实因为establish只能vt，那么当作分词短语还马马虎虎说的过去，我第一眼认为和but后面的结构non-parallel了，但是考虑到整个as a method....只是作为状语，没有理由要求和but后面的结构parallel；但是新的问题又来了，前面是个纯粹的状语，那么but明显就多余了。

我个人倒偏向于C，因为as early as...结构当作前一个clause的状语也说的过去，况且这个位置也是能找到的最好的位置。请大牛们指正~~

偶同意C,为什么说a well-established method of mineral extraction
与as early as the eighteenth century无法连接? as early as 不是比较呀?Leaching从A看来应是一个method,而不是想表达Leaching作为一个method是什么时候well-established.

谢谢LSE

个人觉得E 错不在完成式分词做定语(是前一个分句的谓语），而是well established 修饰method/extration改变原意或有歧义。E的过去完成时应该最好。

答案是B，觉得不对。

可能是C吧？

请大N指点

谢谢指正！