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作者: zcooles 时间: 2010-8-17 19:56
答案给的B
我想问的是B中while后面的结构，那个是省略吗？
是不是可以还原成...while they are introducing some...的形式？
如果是这样的话，为什么be动词没有还原呢？
前面并没有出现过be动词呀作者: MarilynR 时间: 2010-8-18 06:45
比如SVO,whileSVO。当S V 一样是，可以省略为SVO,while doing。的形式作者: zcooles 时间: 2010-8-19 06:51
