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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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To me a structure of the sentence has the following logic:
using 2/3 rule:
While vs. but - While wins. so we can eliminate D&E
In C "which" modifies time
A says that "Industrialization and methods of insects contorol..having gone (sounding awkward at least) unregulated." I think the meaning is distorted.
So B wins.
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