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题库 / Prep2007E1-SC-97
Industrialization and modern methods of insect control have improved the standard of living around the globe while at the same time they have introduced some 100,000 dangerous chemical pollutants, having gone virtually unregulated since they were developed more than 50 years ago.
while at the same time they have introduced some 100,000 dangerous chemical pollutants, having
while at the same time introducing some 100,000 dangerous chemical pollutants that have
while they have introduced some 100,000 dangerous chemical pollutants at the same time, which have
but introducing some 100,000 dangerous chemical pollutants at the same time that have
but at the same time introducing some 100,000 dangerous chemical pollutants, having
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有没有人因为B不平行而选了A？根据GMAT平行大过天的原则........然后就踩了他的坑。有一个看起来有点白痴的疑问——while是否也能和and，but一样作为平行标志词？
while应该可以省略的，曼哈顿说只有FANBOYS是要前后一定平行，即for, and, nor, but, or, yet, so
有人问了这个问题，这是RON的回答："while" is a subordinating construction, not a coordinating one, so it doesn't have the same strict parallelism requirements as does "but".
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