GMAT Preparation: Grammar rules for Sentence Correction

Students preparing for Sentence Correction on GMAT, often wonder how much English Grammar do they need to know as part of their GMAT preparation, to do well in Sentence Correction.

After all, the time that you have at hand, is limited and GMAT preparation is not just about Sentence Correction. So, you would want to only devote only as much time towards Sentence Correction, as is absolutely required. 

Let's first start with the basic question: where does English grammar come into the picture in sentence correction?

Grammar's role

In order to understand Grammar's role in GMAT preparation, let's first understand what grammar is. Grammar is basically a tool that helps us articulate the intended meaning of a sentence, in the best possible manner; through Grammar, we understand what pronouns to use, what verb to use, what tense to use, what modifiers to use etc. so that the intended meaning of the sentence gets depicted appropriately. So, Grammar is basically a tool that helps us articulate the intended meaning of a sentence, in the best possible manner.

Hence, as the illustration below depicts, wrong sentences are those where what the sentence wants to say (in other words, what the sentence logically intends to convey) is different from what the sentence is actually saying (in other words, what the sentence grammatically conveys). 


Grammar 2

On the other hand, as the illustration below depicts, correct sentences are those where what the sentence wants to say (in other words, what the intended meaning of the sentence) is aptly supported by the way the sentence is actually articulated.(in other words, what the sentence grammatically conveys). 

 Grammar 3

Hence on GMAT, our knowledge of grammar enables us to evaluate the five options available to us, to pick the option that best articulates the intended meaning of the sentence. After all, GMAT sentence correction is all about evaluating the five options to choose the option that best articulates the intended meaning of the sentence/author. Hence, a basic understanding of grammar provides us with an effective tool for analysing the five answer choices, to arrive at the right answer.

How much Grammar is enough!

As part of your GMAT preparation, how much grammar do you really need to know? Thankfully, you do not need to be a grammar Guru to score well on GMAT sentence correction. Proficiency with certain grammar concepts, is all you need, to do justice to sentence correction.

Let's look at which grammar concepts you need to be proficient in, for Sentence correction section in your GMAT preparation:

i) Parts of speech

A basic understanding of the various parts of speech, is crucial as part of GMAT preparation:

a) Nouns: A noun is a word used to name a person, animal, place, thing, and abstract idea. For example: Peter, Chicago, lion, laptop, festival etc. Especially make sure you look at a lot of examples of abstract nouns, because that's what the test takers find most challenging to identify.

b) Pronouns: A pronoun can replace a noun or noun-phrase. Pay specific attention to relative pronouns (which/that/who/whom/whose/when/where), for these are quite extensively tested on GMAT. For example: he, it, they, them, us etc.

c) Verbs: A verb is a word that expresses action or otherwise helps to make a statement. It should be noted that there can be no complete sentence without a verb. For example: eat, sing, is, was, run etc.

d) Adjectives: Adjectives are words that describe (modify) another person or thing in the sentence. Generally, the questions that adjectives answer are: which, what kind, and how many. For example: tall, beautiful, humorous, lazy etc.

e) Adverbs: Most adverbs modify verbs (though adverbs can also modify adjectives or other adverbs) and answer the questions: how, when, where, how much and why. For example: slowly, incrementally, quickly etc.

f) Prepositions: A preposition is a word or phrase that links nouns, pronouns and phrases to other words in a sentence. For example: of, for, with, about, beneath etc.

g) Conjuncitons: Conjunctions are parts of speech that are used to link words, phrases, and clauses. For example: and, or, because, although, either...or.., yet etc.

Don't worry about the part of speech interjections:).

ii) Clauses and Phrases

A Clause is a group of related words, containing a subject and a verb. On the other hand, a Phrase is a group of words that does not contain both a subject and a verb.

There are two types of Clauses:

a) Independent Clauses: An Independent Clause is a clause that can stand by itself as a complete sentence and still make sense. For example:

Jerry likes strawberry.

He worked.

b) Dependent Clauses: A Dependent Clause is a clause that cannot stand by itself as a complete sentence. For example:

because it was not workig properly

which was parked in the basement

From this discussion on Independent Clauses and Dependent Clauses, it should be evident that:

All sentences are clauses, but all clauses are not sentences. Clauses that are complete sentences, are called Independent Clauses, while clauses that are not complete sentences, are called Dependent clauses.

Another crucial topic in the discussion of Clauses, is the concept of Coordinating conjunctions and Subordinating conjunctions: Coordinating conjunctions (for example, for, and, not, but, or, yet, and so) connect two Independent clauses, while Subordinating conjunctions (for example, because, although, while, until etc.) mark the beginning of a Dependent clause.

iii) Run-on sentences

A very important often-tested conecpt vis-a-vis our discussion on clauses, is run-on sentences. Remember that whenever we have two Independent Clauses, there are only two ways to connect those Independent Clauses: through a semicolon or through a Coordinating conjunction. For example:

Peter likes basketball, but his brother likes soccer.
- Here, the two Independent clauses are correctly connected by Coordinating conjunction but.

However, when two Independent clauses are connected by only a comma, that construct is called a run-on sentence, and is always wrong. For example, following is a run-on sentence:

Peter likes basketball, his brother likes soccer.
- Notice that the two Independent clauses in the above sentence are incorrectly connected by just a comma. Hence, the above sentence is a run-on sentence, and is wrong.

iv) Participles and Gerunds

Both Participles and Gerunds are verb forms (words derived from verbs). When verb forms are used as adjectives (for example, smiling baby, eaten apple) they are called participles. On the other hand, when verb forms are used as nouns (for example, smiling is good for health) they are called gerunds.


Sentence correction section as part of your GMAT preparation, is not about a heavy dose of English grammar.

As we have summarized above, there are only few concepts in grammar that you need to be proficient in. Of course, we have addressed each of the topics rather superficially above, and is not comprehensive enough, for your GMAT preparation. The intent of this article was to provide you with a gist of what grammar on GMAT entails. There is much more to each of the above topics.

The good news

Our book Sentence Correction Nirvana is your companion in GMAT preparation. In fact, the entire Grammar section of Sentence Correction Nirvana is available for free preview, at Each of the above topics is discussed in detail and would suffice for all your Grammar needs for Sentence Correction, as part of your GMAT preparation!