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.
- as a method of the extraction of minerals, it was well established
-it 多余。
- as a method of the extraction of minerals well established
- was a well-established method of mineral extraction
与as early as the eighteenth century无法连接。
- 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。
- 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。
[此贴子已经被作者于2004-7-9 14:40:34编辑过] |