19. 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

A: 两个they不是指代同一个对象

B: correct

C: 两个they不是指代同一个对象

D: but不能引导条件状语从句

E: 同上

大家是我看过的所有讨论稿中的 NN.

谢谢楼上的给我鼓励。可是如果是我那样理解的话这题就做不出来了。

还有代词指代的问题，什么时候才可以判定指代混乱啊。我们到底该如何判断呢？

是通过单复数还是逻辑意思啊？

既然逻辑都可以判断，那怎么又会出现混乱的问题呢？

好混乱啊．总之就是又混乱又烦躁

为什么A的问题是恰恰在于中间加了个they have，导致后面的having gone不再修饰其应该修饰的Pollutants。?

还是不明白啊.请NN把问题嚼烂了给我，对不起，实在想不出来。

还有疑问就是后面说since they were developed more than 50 years ago. 这里的代词指代的为什么一定是POLLUTANTS,而不是 Industrialization and modern methods of insect control ?

我的意思是说发展了很多年的为什么不能指工业化和现代方法来做的昆虫控制,而是说的污染呢?

此题确实很诡异..

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.

1）此句中的that应该是指代pollutants。但是这就很奇怪，你可以说regulate methods。但是可以说regulate pollutants吗？

2）从语法上来讲，they应该指代pollutants。从逻辑上来讲，they应该是指代methods。但是如果they是指代methods的话，它们之间的距离会不会太遥远了一点？

3）如果把while引导的状语（是壮语吗？）拿掉的话，句子就变成Industrialization and modern methods of insect control have improved the standard of living around the globe since they were developed more than 50 years ago. 这样就比较清晰了。

我觉得A的错误在于用了having做定语修饰了pollutants,现在完成时的-ing形式不能在句子里作定语。

但是我怎么觉得at the same time 和 while 意思重复了呀？？

我想知道DE除了lz说的错误，其他还哪错了