GMATPrep test #1

LuLuanna

Source = GMATPrep test #1

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. [size=14.007px].

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


OA: B
a项是having 作状语这里错了吗？
b项while+doing 不明白为什么可以这么用，求解~！
然后c项为什么不对呢？

spings

从句意看，having gone virtually unregulated....是直接修饰前面的名词pollutants, 此处用从句最好，另外，如果直接修饰前面的名词，用having gone比较奇怪，过去分词直接即可，还有直接修饰前面的名词，不需要逗号分隔。 选项C，如果你放回句子中看，结构是：主句+while引导的从句+连词and， 这时主语是谁呢？当然是主句的主语，意思就全变了。希望解释对你有用。。。。

LuLuanna

spings 发表于 2017-3-23 23:37
从句意看，having gone virtually unregulated....是直接修饰前面的名词pollutants, 此处用从句最好，另外 ...

同意！               

emmahiggins09

comma having done 这种形式表示的是发生在主句中的谓语动词之前的动作，在这里显然是不对的。

LuLuanna

emmahiggins09 发表于 2017-3-24 14:41
comma having done 这种形式表示的是发生在主句中的谓语动词之前的动作，在这里显然是不对的。 ...

同意！