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题库 / Prep2007E1-SC-130
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, and have
but introducing some 100,000 dangerous chemical pollutants at the same time that have
but at the same time introduce some 100,000 dangerous chemical pollutants, having
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A错在having＋未划线句作为伴随状语，就近修饰前面while状语从句的主语industrialization and modern methods，但应该修饰chemical pollutants。 B是正确答案。C错在have gone的是pollutants而不是industrialization and modern methods。D错在while可以直接加doing而but不能，DE的but后面都应该改为have also introduced或者they have also introduced。而且E最后的having错误同A。
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