GMAT Sentence Correction 101: Back to the Basics!
Most efforts to combat such mosquito-borne diseases
like malaria and dengue have focused either on the vaccination of humans or on exterminating mosquitoes with pesticides.
A like malaria and dengue have focused either on the vaccination of humans or on exterminating
B like malaria and dengue have focused either on vaccinating of humans or on the extermination of
C as malaria and dengue have focused on either vaccinating humans or on exterminating
D as malaria and dengue have focused on either vaccinating of humans or on extermination of
E as malaria and dengue have focused on either vaccinating humans or exterminating
The question consists of a given sentence, part of which is underlined. The underlined segment may be short, or it may include most or even all of the original sentence. The five answer choices are possible replacements for the underlined segment.
In all Sentence Correction questions, choice (A) is exactly the same as the underlined portion of the sentence above it. The other choices, however, offer different options. The question you are answering in Sentence Correction is always the same: which of the answer choices, when placed in the given sentence, is the best option of those given, in terms of grammar and meaning. Several principles will be tested at once, typically.
Answer choice (A) is not always wrong. The original sentence, (A), is the correct answer just as often as the other answer choices—about 20% of the time.
Ideal sentence and correct answer choices are different things
Sentence Correction questions ask for the best option of those given, not the best option in the universe. Sometimes you may feel—and rightly so—that all the answers, including the right one, “sound bad.” Correct GMAT Sentence Correction answers never break hard grammatical rules, but these answers can sound formal or even awkward. Your task is to evaluate the given answer choices, not to create the ideal sentence. Never rewrite the sentence in your own words.
The GMAT exploits the fact that the English you hear is often riddled with grammatical mistakes. Thus, your ear may not be trained so well to catch the errors that the GMAT cares about. To surpass the limitations of your ear, you must rigorously compare the given answer choices to each other, using principles of sound grammar and clear meaning to determine the best available option.
Understand and Split
Don’t read the choices. Rather, scan up and down to find splits.
• The beginning of the choices is a great place to look. The five choices must
differ in their first word (otherwise, that word wouldn’t be underlined).
• The end of the choices must also produce a split.
• Finally, if you noticed something wrong in your initial reading, use that issue
in your search.
Splitting Theory
- Read the original sentence carefully, and make sure that you understand it.
- Scan the choices vertically for splits.
- Choose an easy split to start with.
- Make your decision on the first split.
- Write down ABCDE and cross out the choices you've eliminated.
- Re-split the remaining choices, and eliminate until you have one answer left.
- Put your final answer back into the original sentence.
Let's shovel the dirt
Most efforts to combat such mosquito-borne diseases like malaria and dengue have focused either on the vaccination of humans or on exterminating mosquitoes with pesticides.
A like malaria and dengue have focused either on the vaccination of humans or on exterminating
B like malaria and dengue have focused either on vaccinating of humans or on the extermination of
C as malaria and dengue have focused on either vaccinating humans or on exterminating
D as malaria and dengue have focused on either vaccinating of humans or on extermination of
E as malaria and dengue have focused on either vaccinating humans or exterminating
Read the original sentence carefully, and make sure that you understand it.Most efforts to combat such mosquito-borne diseases like malaria and dengue have focused either on the vaccination of humans or on exterminating mosquitoes with pesticides. The sentence talks about the efforts, which is the main subject and "have focussed" is the main verb. The efforts have been on two things -- vaccination of humans and extermination of mosquitoes. Great. Let's see where that takes us. I will also try to note that "like" has been used to introduce examples, which my friends and GMAT Club tells me is a cardinal sin on the GMAT. Probably that is going to be my first split.
Scan the choices vertically for splits.It is easy to notice that "like" and "such as" are the strongest contenders for a split. So right now my splits are AB and CDE. The other split can be the "either- or" split.
Choose an easy split to start with.Like vs Such as is straightforward. So I will split as AB and CDE.
Make your decision on the first split"Like" cannot be used to introduce examples. So I will eliminate A and C. Also the clause "such.......like" does not make any sense.
Write down ABCDE and cross out the choices you’ve eliminated.A B C D E
Re-split the remaining choices and eliminate until you have one answer left.Here comes the tricky part. Let's look at the other options:
Most efforts to combat such mosquito-borne diseases
like malaria and dengue have focused either on the vaccination of humans or on exterminating mosquitoes with pesticides.
C as malaria and dengue have focused on either vaccinating humans or on exterminating
D as malaria and dengue have focused on either vaccinating of humans or on extermination of
E as malaria and dengue have focused on either vaccinating humans or exterminating
Now, I know that Either and Or must be EXACTLY parallel.
In option C, either is preceded by the preposition "on", but or is followed by the same. So C is not parallel and out.
In option D, either is preceded by the preposition "on", but or is followed by the same. So C is not parallel and out.
In option E, on is followed by a complete "either.....or......" clause with ing phrases after each. So E is seemingly parallel. E is in!
Note that CD and E are mini splits within a split (A GMAT favourite)
Put your final answer back into the original sentence.Upon substituting the answer choice E I get,
Most efforts to combat such mosquito-borne diseases as malaria and dengue have focused on either vaccinating humans or exterminating mosquitoes with pesticides.This seems quite parallel and logical in meaning and construction.
E is the winner.
In this way, I confirm that the meaning and grammar of choice (E) is completely accurate. At this point on the test, I would click on this choice and move on.
Please note that I did not HAVE to consider the splits and the mini splits. My process will accelerate with more practice and relative ease with GMAT-esque sentences. The example is used as a basic framework to approach SC problems.This is the first part of the Sentence Correction 101 Series. One SC article every week. Watch this space next Friday for the next.
But in E "As" is used in order to give examples, "As" should be used to compare clauses, right?