prep 130语法一道~ 关于while

指弹之水

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.

(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, and
have
(D) but introducing some 100,000 dangerous chemical pollutants at the same time that have
(E) but at the same time introduce some 100,000 dangerous chemical pollutants, having
这题答案为B. PREP 的解释是说，while在这里表示的是与。。同时的意思，同时也是原文要表达的意思从而否定了DE. 我的疑问在于，如果while表达的是与。。同时，岂不是和at the same time 语意重复？我觉得这里while应该表达的是转折。不知道我的想法对不对

nadou1

太难了，学不来












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蓝狮爱我

我一直有纠结也是觉得 at the same time 和while 重复

alexgong

我也觉得while有疑问~   如果不是表示时间状语，为什么能省略 they are？？
while为转折词，比较省略也 不能没有are吖

指弹之水

题目前面说是improved the standard of living ，后面说  

introduce chemical pollutants 不就是转折的关系吗？

llqq1220

如果while表转折逻辑意思就不对了呀。。