标题: industrialization and modern methods对于while用法的疑惑 [打印本页] 作者: viewlam 时间: 2017-4-5 11:00 标题: industrialization and modern methods对于while用法的疑惑 Industrialization and modtern 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 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
对于这题的while我有两个疑惑：
1.while不是代表着“当...的时候”吗，也具有同时的意思，这不就和at the same time句意重复了吗？
2.while不是也有表示转折的意思吗，我看到rule out D的理由都是说因为原意没有转折的含义