GWD1-31(大全969)

xyredpoppy

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
       

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

3. was a well-established method of mineral extraction
       

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

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

   Answer: C

前人讨论没有看到定论：

extraction和as early as这两部分怎么能连在一起了....

前人讨论没有看到定论：

extraction和as early as这两部分怎么能连在一起了....

[此贴子已经被作者于2009/9/2 14:03:02编辑过]

xyredpoppy

顶~

xyredpoppy

再问~

xyredpoppy

...告诉我一下吧~

bonniexiong

应该这么说，虽然不是很好，但在本题中确实最好的选项，因为其他选项的错误更明显