标题: GWDTN1-41 [打印本页] 作者: poppy9696 时间: 2010-1-8 13:32 标题: GWDTN1-41 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. as a method of the extraction of minerals, it was well established B. as a 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 mineral that was E. had been a method of mineral extraction, well established
答案C.
E为什么不对？ 有点过去的过去意思吧？作者: mba11 时间: 2010-1-8 14:38
as early as 18th century.... 不是过去的过去；E 比较上口，但时态不对。作者: poppy9696 时间: 2010-1-9 12:14
恩。明白了。 谢谢mba11!