GMAT语法每日一题详解（3）

3.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

原文意思： 工业化的杀虫方法提高了全球的生活水平而与此同时引入了很多化学污染物， 这些化学污染物没有得到很好的控制。

题目分析： A 中 introduced 和前面提高生活水平的发起者是一样的， 没有必要加 they， 干掉。 B 把 they去掉了，留着。C 有加了 they，干掉。D 把 at the same time，B 的感觉是提高了生活水平而与此同时引入化学污染物 D 感觉是提高了生活水平而引入化学污染物与此同时， 感觉哪个逻辑更顺，显然是 B。E 用 having，前面还用逗号，谁做出了 having gone 这个动作，不知道，歧义太多，不好！