insect control

[MichelleW1982]

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


Answer B


I agree with the answer, no question there. HOWEVER, the in the correct answer: "have improved" and "introducing".....these two are not parallel? Can anyone explain this? Thank you!

[Vemuri]

A. Incorrect pronoun reference.
C. Incorrect pronoun reference.
D. Awkward construction.
E. Awkward construction.

B --> This is the best option among the choices. Also, the participle 'introducing' correctly fits in the sentence.

[mals24]

I think you can easily boil down the options to A and B.

Well you are right 'introducing' is not parallel to 'have improved'. However the use of 'introducing' is correct in this sentence because it rightly shows an ongoing action. Industrialization and modern methods still introduce these chemical pollutants. Hence we need to use the present participle 'introducing'.

Also in A 'having' incorrectly modifies the subject of the previous clause, which is 'they' in this case. So you can look for other errors as well to choose between A and B, if you are not sure about the parallelism part.

[bmlaud]

I think you can easily boil down the options to A and B.

Well you are right 'introducing' is not parallel to 'have improved'. However the use of 'introducing' is correct in this sentence because it rightly shows an ongoing action. Industrialization and modern methods still introduce these chemical pollutants. Hence we need to use the present participle 'introducing'.

Also in A 'having' incorrectly modifies the subject of the previous clause, which is 'they' in this case. So you can look for other errors as well to choose between A and B, if you are not sure about the parallelism part.

The choice B for sure is the best among available choices, but it lacks parallelism. The use of 'have' in the second part would make the sentence parallel and yet convey an on going action. Why to use a participle then?

[karmayogi]

I think you can easily boil down the options to A and B.

Well you are right 'introducing' is not parallel to 'have improved'. However the use of 'introducing' is correct in this sentence because it rightly shows an ongoing action. Industrialization and modern methods still introduce these chemical pollutants. Hence we need to use the present participle 'introducing'.

Also in A 'having' incorrectly modifies the subject of the previous clause, which is 'they' in this case. So you can look for other errors as well to choose between A and B, if you are not sure about the parallelism part.

The choice B for sure is the best among available choices, but it lacks parallelism. The use of 'have' in the second part would make the sentence parallel and yet convey an on going action. Why to use a participle then?

Simply because that is not in the correct answer option. We all agree that answer has to be between A and B. Now let's examine A and B. Use of "having" after comma means it is referring to complete clause, "...while at the same time...pollutants," before it. However, what went unregulated? Pollutants. Hence, we need a restrictive clause. As both participle and present perfect are correct in this case, B is the best option. However, I would agree that replacing participle with preset perfect in option B would make it better, but we don't have that as an option.

[mals24]

Even I agree with you bmlaud on the parallelism issue. well I think ultimately in GMAT we have to choose the best available option. Many times the correct answer also has some flaws in it. So its not about choosing the perfect answer but the best amongst the given options.

So B is not the perfect choice, but the best available choice.