GWD-TN-1-Q41

加州女孩

GWD1-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.



A.asa method of the extraction of minerals, it was well established

B.asa 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 mineralthat was

E.had beena method of mineral extraction, well established
答案是C  请路过的大仙帮我解释哈子每个选项的错误或正确的原因吖，尤其是E，为什么不用过去完成时啊，根据题目 but until about 25 years ago ，不是证明之前的动作发生在过去的过去吗？严重谢过

flames001

"and"  已经足以说明时间顺序了

gracezz

觉得E不好是因为well established 有修饰那个extraction的感觉。。。

gracezz

帮你顶一下~~~

加州女孩

天啊，好吧，UP UP ~

加州女孩

斑竹，救命啊，是不是问题太弱啦？