[求助]困惑很久

fionajiang

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

这里到底用什么时态? 从意思上看,好想是比25 years ago还要早,就是过去的过去,

icando0512

答案是哪个?

fionajiang

我也不知道,C和E都看见过,希望大家讨论.

我个人支持E.

就醉一生

C

fionajiang

NN能说一下理由吗?

就醉一生

个人意见

E:well established修饰成问题，过去分词一般就近修饰。

但是原文并不是说 mineral extraction was established......

mbamom

应该是C吧，此题并未说该方法在过去某个时间停止，而只是说在25年前人们才认识到细菌在其中的作用，所以用had been不对