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.
- as a method of the extraction of minerals, it was well established
- as a method of the extraction of minerals well established
- was a well-established method of mineral extraction
- was a well-established method of extracting mineral that was
- had been a method of mineral extraction, well established
一开始看到C时,我认为是正确答案。可再看到E后,我又认为E强调了时间的对比,显然这里讲了两个时间,对过去的过去采用had been会更合适。而且,well established修饰前面a method of...的中心词method也说得过去。
可答案为什么是C呢?
虽然E的结构略显复杂,没有C的结构那么紧凑。可是,无论结构多么紧凑,时态总要先保证正确吧!那么,这里为什么用was 而 不用 had been呢?
请各位NN指教。
我自己想到的一个解释是,中间用了连词 but,事实上这是两个句子,那么对于第一个句子而言,其时间词只有一个,所以用was。不知这样理解正确否? |