Q41:

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

答案是C，但我觉得E对阿，早在18世纪。。。25年前（过去时）=〉前半部分用过去完成时

A，it 多余了，两个主语了。（还一个leaching)

B, 逻辑错了。那个established本来应该修饰leaching,现在修饰extraction了

C，..........

D，extracting mineral 这个也意思变了。还有就是that be简单系表结构罗嗦。

E，established做定语位置错。做谓语没be且双谓语了。时态错：我觉得看时态要联系句子逻辑关系。不能只看有两个时间对比就用完成时态。你看啊，前面说的是LEACHING是个...的方法。后面的时间说的是：miner没意识到.....你看主语就知道他们逻辑上不是一个东西啊。我的意思是说，如果你要用完成时态，那就是在两个前后时间段比同样一个东西。而这个题里不是说的一个东西。所以不用完成时态。就好象两个发生在过去的没有直接关系的东西，虽然时间上是不同，那难道就不能用过去时么？？

呵呵，一点想法.只是参与讨论！

我认为as early as the eighteenth century是一个副词性短语，只能修饰动词establish,不能修饰名词method，所以倾向于E

C的表达虽然简洁，但as early as the eighteenth century紧跟在method of mineral extraction 后面，变成as early as the eighteenth century在修饰method了，不合适，除非as early as the eighteenth century这个短语可以当作形容词来用

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

這題我再問

A/B兩個選項

除了A的it

B的句子結構

出現問題外

1.那個as....有沒有問題????

2.遇到這樣的結構

我可以理解成同位嗎??

比方說as a method of the extraction of minerals, it was well established

是拿來修飾leaching的.....

有很多分词定语的短句修饰主语的后置或者前置，都按你说的紧跟名词了？

A/B没谓语

E，well established做什么成分？修饰得话，有修饰对象得歧异，做动词缺少一个be。问题在于一个逗号，使其成分作用不清