GMAT Sentence Correction – Sentence Structure

MBABuddy Sentence Correction Series

This article is a first in a series of articles meant to dive deep into the rules of the English grammar to nail the GMAT Sentence Correction Article. If you didn’t already, check out the GMAT Verbal Sentence Correction Cheat Sheet we created. This introductory article will discuss basic sentence structure and comma usage. A sentence is comprised of clauses, phrases, and at the very least a subject and a verb.

Subject and Verb

Every sentence should have, at a minimum a subject and a verb. The subject is a person, place, idea, or anything that is doing an action. The verb is the action. For example, in the sentence “Daniel eats”, “Daniel” is the subject, and “eats” is the verb. In the sentence “Jane is studying”, “Jane” is the subject, and “is” is the verb. A subject is typically a noun, pronoun, gerund, or infinitive (don’t worry, we’ll get to it soon).

There is one common exception, though. If the sentence is a command, then the subject is ‘hidden’. For example in the sentence “Do the dishes!”, the subject is “you”, and the verb is “Do”.

A sentence can have more than one subject and verb. For example, “Jane is studying, but Daniel studied earlier” has two subjects (“Jane,” and “Daniel”,) and two verbs (“is,” and “studied”, respectively.) Each part of the sentence that has a subject and a verb is called a “clause”.


Each sentence can consist of one or more clauses. Words connecting clauses are called “conjunctions”. Common examples of conjunctions include ‘but, ‘although’, ‘nevertheless’, ‘nor’, ‘or’. The full list, is much longer, but the idea remains the same.

In the sentence “I like potatoes, but she likes bananas” there are two clauses. The clause “I like potatoes” is considered an ‘independent clause’. The second phrase “but she likes bananas” is an independent clause, because it starts with a conjunction. One more tip to note is that a sentence must have an independent clause, and cannot have more than one dependent clause.

A conjunction can also appear in the first clause, making it an independent clause. For example: “While I study for the GRE, all of my friends are studying for the GMAT.”

Comma Usage

There are special conjunctions that mandate usage of a comma, or mandate not using a comma.

Coordinating conjunctions include ‘and’, ‘but’, ‘for’, ‘nor’, ‘yet’, ‘or’, and ‘so’. These conjunctions must follow a comma when connecting an independent clause with a dependent one.

Example: Sentence correction questions are difficult, so you better study. <no pressure>

The following conjunctions should never follow a comma when connecting an independent clause to a dependent clause:  ‘if’, ‘before’, ‘after’, ‘until’, ‘unless’, ‘whether’, ‘in case’, ‘when’, ‘where’, ‘that’, and ‘while’.

In all other conjunctions, a comma is optional.

Semicolon Usage

Typically, a semicolon is used to connect to independent clauses that are closely related by topic.

For example: Some people solve sentence correction questions by learning tips and tricks; others utilize a deeper understanding of the underlying grammar rules.

A semicolon can also be used to separate items in a comma separated list, to help distinguish between independent clauses that contain many commas, and to separate independent clauses connected by transition phrases or adverbs (we’ll get there).


Don’t worry if you get this wrong. This question includes topics not yet discussed in this article. But we explain why each option is right or wrong after you take it, so go ahead!

Select a choice to replace the underlined portion of the text so that the sentence is most grammatically correct.

Last May, a famous painting with a view of the golden gate bridge over the water sold for $1 million and it was the highest paid at auction that month.


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