请教~~~~~请教~~~~~~~谢谢！

zlin0222

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.

A. while at the same time they have introduced some 100,000 dangerous chemical pollutants, having

B. while at the same time introducing some 100,000 dangerous chemical pollutants that have

C. while they have introduced some 100,000 dangerous chemical pollutants at the same time, which have

D. but introducing some 100,000 dangerous chemical pollutants at the same time that have

E. but at the same time introducing some 100,000 dangerous chemical pollutants, having
答案：B
请问：while后面引导的是什么从句呢？条件从句的话也解释不通呀？时间状语从句的话不是和at the same time语义重复了吗？

花子落落

表然而没转折~~

zlin0222

那为什么用introducing而不是introduced呢？这样不是和前面的improved平行吗？

zlin0222

再顶一下~希望能有人帮我解答啊~~~谢谢！！

yougushizi

while+doing强调两个动作同时发生。

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.

A. while at the same time they have introduced some 100,000 dangerous chemical pollutants, having

B. while at the same time introducing some 100,000 dangerous chemical pollutants that have

C. while they have introduced some 100,000 dangerous chemical pollutants at the same time, which have

D. but introducing some 100,000 dangerous chemical pollutants at the same time that have

E. but at the same time introducing some 100,000 dangerous chemical pollutants, having
答案：B
请问：while后面引导的是什么从句呢？条件从句的话也解释不通呀？时间状语从句的话不是和at the same time语义重复了吗？

-- by 会员 zlin0222 (2010/8/10 14:31:35)

zlin0222

噢。。谢谢啦！~~