PREP语法(findjuhl整理的55题)

55. 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 pollutant, having

answer B

划线部分的while后introducing some 100000 dangerous chemical pollutants是什么成分？　while 之后对句子结构有什么要求？做题时候就是以为while之后要跟句子才没有选B

基础太差。。。。

再UP

再再顶，呼唤NN

问下，since they were developed more than 50 years ago.

这个they指代的是什么？

指代主语的主语

Industrialization and modern methods

根据答案，我觉得此处they应该指代pollutants吧。因为that后整个是修饰pollutants的。所以不能选A，因A中第一个they指的是主句主语：industrialization and modern methods

while at the same time introducing some 100,000 dangerous chemical pollutants that have gone virtually unregulated since they were developed more than 50 years ago.

请nn指正！