GWD10-31没有讨论过的部分

abcd1234czyf

gwd 10-31
Q31:

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



答案是C
这个可以理解。
我的问题是1。A为什么不对？
                 2。C选项中的as early as ,,,是作为状语修饰整个句子还是什么？
谢谢啦

michaelmay17

假设答案是A的话变为Leaching, the recovery of copper from the drainage water of mines,as a method of the extraction of minerals, it was well established .......................就会出现2个修饰成分放一起引起修饰的错误，而且Leaching 是主语，it也会多余