GMAT Sentence Correction: The Complete Reference

Sentence Correction was one of three question types on the classic GMAT Verbal section, alongside Reading Comprehension and Critical Reasoning. Each question presented a sentence with a portion underlined, and you chose the best version of that underlined portion from five answer choices. Choice (A) always repeated the original text, so selecting (A) meant the original was correct.

SC tested two skill areas. The first was grammar: subject-verb agreement, verb tense, parallel structure, modifiers, pronouns, comparisons, and idiomatic usage. The second was effective expression: clarity, concision, and logical meaning. The exam did not test vocabulary in isolation, spelling, or punctuation rules on their own. It tested whether you could identify errors that affected grammatical correctness, clarity, or meaning.

On the classic GMAT, the Verbal section had 36 questions in 65 minutes. Roughly 11 to 14 of those were Sentence Correction, meaning each SC question needed to take about 60 to 90 seconds.

Every SC question followed an identical format:

1. A sentence appeared with a portion underlined. The underlined section could be a single word, a phrase, or the entire sentence.
2. Five answer choices followed. Choice (A) always repeated the original underlined text verbatim. Choices (B) through (E) rewrote the underlined portion in different ways.
3. You chose the answer that produced the clearest, most grammatically correct sentence. If the original needed no correction, the answer was (A).

A single underlined portion could contain multiple errors. Answer choices often varied on more than one point simultaneously, which meant you needed to evaluate several splits at once. The answer that fixed every error was correct; an answer that fixed one error but introduced another was wrong.

The subject and verb of every clause must agree in number. A singular subject takes a singular verb, and a plural subject takes a plural verb. The rule itself is simple, but the GMAT made it hard by separating the subject and verb with long phrases and clauses.

Patterns that obscure agreement:

• Intervening phrases: A long phrase between the subject and verb can distract you. In "The list of items were long," the subject is "list" (singular), not "items" (plural). The verb should be "was."
• Compound subjects: "The manager and the assistant are here" takes a plural verb. But add "each" or "every" and it stays singular: "Every manager and assistant is here."
• Collective nouns: "The team is ready" (singular in American English). But "The team members are ready" is plural because "members" is the real subject.
• Indefinite pronouns: Words like "each," "every," "anyone," "nobody," and "someone" are always singular: "Each of the students has a textbook."
• Either/or and neither/nor: The verb agrees with the nearer subject. "Neither the manager nor the employees are responsible," but "Neither the employees nor the manager is responsible."

How to test it: Find the subject. Find the verb. Ignore every word between them. Check whether they agree in number.

Verb tense must be consistent and logical within a sentence. The GMAT tested whether the correct tense was used for the context and whether tenses were consistent across related clauses.

Core rules:

• Consistency: Events in the same time frame use the same tense. "She walks to the store and buys milk" keeps both verbs in the present. Switching tenses without a reason creates an error.
• Past perfect: Use had + past participle for an action that occurred before another past action. "By the time she arrived, the store had closed." The simple past ("arrived") marks the later event; past perfect ("had closed") marks the earlier one.
• Present perfect: Has/have + past participle connects a past action to the present. "The company has grown since 2020" means the growth started in the past and continues now.
• Subjunctive mood: The subjunctive appears in two contexts on the GMAT. First, contrary-to-fact statements: "If I were rich" (not "was"). Second, commands and suggestions: "The board requires that he resign" (base form, not "resigns").
• Future tense: "Will" is for predictions and future events, not for established facts or present conditions.

How to test it: Identify the time frame of the sentence. Check that each verb's tense matches when the action occurs relative to other events in the sentence.

Items in a series, list, or comparison must use the same grammatical form. This rule, called parallelism, was one of the most frequently tested concepts on Sentence Correction.

The rule: If a sentence contains a list joined by "and," "or," or a colon, every item must use the same structure. All gerunds, all infinitives, all nouns, all adjectives, or all clauses.

Examples:

• Correct: "She likes hiking, swimming, and running" (all gerunds).
• Incorrect: "She likes to hike, swimming, and to run" (mixing infinitives and gerunds).
• Correct: "The report was thorough, accurate, and timely" (all adjectives).
• Incorrect: "The report was thorough, accurate, and written well" (two adjectives then a participial phrase).

Parallelism also governs comparisons and paired conjunctions:

• Comparisons require parallel elements on both sides: "The new model is faster than the old model" (noun compared to noun).
• Both/and, either/or, not only/but also: The structure after each conjunction must match. "She is both intelligent and hardworking" (two adjectives). "She not only manages the team but also writes the reports" (two verb phrases with objects).

How to test it: When you see a list, a comparison, or a paired conjunction, check that every element uses the same grammatical form. If one item breaks the pattern, that choice is wrong.

A modifier is a word or phrase that describes another element in the sentence. The GMAT tested two modifier errors: dangling modifiers and misplaced modifiers.

Dangling modifiers: A modifier must have a clear subject to describe. If the subject is missing from the sentence or is the wrong word, the modifier dangles.

• Incorrect: "Having finished the report, the computer was shut down." The phrase "Having finished the report" needs a subject who finished it. The computer did not finish the report.
• Correct: "Having finished the report, the analyst shut down the computer." Now "the analyst" is the subject who finished the report.

Misplaced modifiers: A modifier must sit next to the word it describes. Distance creates ambiguity or changes the meaning.

• Incorrect: "The dog barked at the cat wearing a collar." Did the cat wear the collar, or did the dog? The phrase should sit next to "cat."
• Correct: "The dog barked at the cat wearing a collar." Or: "Wearing a collar, the dog barked at the cat."

Limiting modifiers (only, just, almost, nearly) must sit directly before the word they restrict:

• Incorrect: "She only eats vegetables." This implies she does nothing else but eat vegetables.
• Correct: "She eats only vegetables." The restriction now applies to what she eats.

How to test it: Find every modifier in the sentence. Check that it has a logical subject and sits next to the word it describes.

Pronouns must agree with their antecedents in number and gender, and every pronoun must have a clear, unambiguous antecedent.

Number agreement: A singular antecedent takes a singular pronoun; a plural antecedent takes a plural pronoun. "The company announced its earnings" (singular). "The companies announced their earnings" (plural).

Common agreement errors:

• Each, every, one: These are singular even when followed by a plural noun. "Each of the students must submit his or her essay" (not "their").
• Collective nouns: "The team submitted its report" (singular). But if the members act individually, use plural: "The team took their seats."
• Ambiguous reference: A pronoun must refer to one clear antecedent. "When the manager spoke to the assistant, she was angry" is ambiguous. Which person was angry? If the sentence does not make it clear, it is wrong.
• Missing antecedent: A pronoun with no noun to refer to is an error. "The report was late, which caused a delay" is acceptable because "which" refers to the entire preceding clause. But a pronoun with no logical referent at all is always wrong.

How to test it: For every pronoun, find its antecedent. If the antecedent is missing, ambiguous, or disagrees in number, the sentence is wrong.

Comparisons must be logically and grammatically parallel. You can only compare things that are in the same category.

Core rules:

• Compare like to like: "The profits of Company A are higher than those of Company B" (comparing profits to profits). Writing "higher than Company B" compares profits to a company, which is illogical.
• Comparative vs. superlative: Use comparatives (more, faster, better) for two items and superlatives (most, fastest, best) for three or more. "She is the taller of the two" (not "tallest"). "She is the tallest of the three."
• Double comparatives and superlatives: "More faster" or "most fastest" are errors. The comparative or superlative form already includes the comparison.
• Like vs. as: "Like" compares nouns: "She sings like a professional." "As" compares clauses with a verb: "She sings as a professional does." Mixing them up is a common SC error.
• Comparisons with than: The word after "than" must be parallel to what came before. "The new software is faster than the old software" (noun to noun). "The new software is faster than it was last year" (clause to clause).

How to test it: Identify what is being compared. Check that both sides of the comparison are in the same grammatical category and logical class.

Idioms are fixed expressions where a particular preposition or word pairing is required. The GMAT tested whether you knew which preposition or structure followed a given word.

Common idioms that appeared on the GMAT:

The challenge with idioms is that there is no underlying logic to memorize. "Credited with" is correct because it is the convention, not because "with" makes more sense than "for." The only strategy is exposure and practice.

How to test it: If you see a preposition paired with a verb or adjective that looks unusual, check whether the idiom is correct. If you are unsure, defer to the other splits in the question and use idiom as a tiebreaker.

Beyond grammar, SC tested whether a sentence communicated its meaning clearly and efficiently. Three principles governed this part of the test.

Clarity: The sentence must have a single, unambiguous meaning. If a sentence can be read two ways, it is wrong. "The professor told the student that the exam was hard" is clear. "The professor told the student the exam was hard about the deadline" is ambiguous and therefore wrong.

Concision: When two answers are both grammatically correct, the shorter one is preferred. Redundancy is always an error. Common redundant patterns include "annual...per year," "end result," "past history," "future plans," and "new innovation." Wordiness is not always wrong, but when the choice is between a concise correct sentence and a wordy correct sentence, choose concise.

Logical meaning: The sentence must make sense. "The temperature was so hot that the road melted" is illogical because temperature is not "hot" (it is "high"). "The number of cars increased, which means fewer people walked" is illogical because more cars do not necessarily mean fewer walkers. The GMAT designed answer choices that were grammatically correct but changed the meaning of the original sentence. Those choices were wrong.

How to test it: After checking grammar, read the sentence for meaning. Does it say what it should? Is it ambiguous? Is any phrase redundant? If two answers are both grammatically correct, choose the clearer and more concise one.

The most effective approach to SC questions uses the split method: identify where the answer choices differ, then eliminate based on those splits.

Step 1: Read the full sentence. Do not jump to the answer choices. Read the entire sentence first to understand its meaning and spot obvious errors.

Step 2: Scan the answer choices for splits. Look at the first word or phrase of each choice. Group the choices by how they handle the first split. For example, if choices (A) and (C) use "was" and (B), (D), and (E) use "were," you have a subject-verb agreement split.

Step 3: Eliminate using the easiest split first. If you can determine that "was" is correct, eliminate (B), (D), and (E) immediately. If "were" is correct, eliminate (A) and (C). This cuts the field in half before you examine anything else.

Step 4: Compare the remaining choices on the next split. With two or three choices left, look for the next difference. Apply the same logic: determine which form is correct and eliminate the others.

Step 5: Check the remaining answer for meaning and concision. When one choice remains, verify that it produces a clear, logical sentence. If two choices survive all grammar splits, choose the shorter, clearer one.

Time management: Spend no more than 90 seconds per question. If you are stuck between two choices, eliminate based on concision and move on. Do not let a single SC question eat time from Reading Comprehension.

Original sentence:

The board of directors, along with the CEO and the CFO, were expected to announce the merger by the end of the quarter.

Answer choices:

(A) were expected to announce the merger (B) was expected to announce the merger (C) are expected to announce the merger (D) is expected to announce the merger (E) had been expected to announce the merger

Analysis:

Step 1: Read the full sentence. The sentence describes an expectation about a board announcement. The subject is "The board of directors," with an intervening phrase "along with the CEO and the CFO."

Step 2: Identify the split. The choices differ on the verb: "were" (A), "was" (B), "are" (C), "is" (D), "had been" (E). This is a subject-verb agreement split combined with a tense split.

Step 3: Find the subject. The subject is "The board of directors." The phrase "along with the CEO and the CFO" is a modifier, not part of the subject. "Board" is singular. The phrase "along with" does not make the subject plural. Only "and" creates a compound subject.

Step 4: Eliminate based on agreement. A singular subject needs a singular verb. "Were" (A) and "are" (C) are plural. Eliminate (A) and (C).

Step 5: Check the remaining choices for tense. "Was expected" (B) is past tense. "Is expected" (D) is present tense. "Had been expected" (E) is past perfect. The sentence says "by the end of the quarter," which indicates a current expectation about a future event. Present tense "is expected" fits. Past tense "was expected" implies the expectation is over. Past perfect "had been expected" requires a second past action, which the sentence does not provide. Eliminate (B) and (E).

Correct answer: (D) is expected to announce the merger

Original sentence:

The new policy was designed to reduce costs, to improve efficiency, and increasing customer satisfaction.

Answer choices:

(A) to improve efficiency, and increasing (B) to improve efficiency, and to increase (C) improve efficiency, and increase (D) improving efficiency, and increasing (E) to improve efficiency, and increase

Analysis:

Step 1: Read the full sentence. The sentence lists three goals of the new policy: reduce costs, improve efficiency, and something with customer satisfaction.

Step 2: Identify the split. The choices differ on whether the second and third items use infinitives ("to improve," "to increase"), gerunds ("improving," "increasing"), or bare verbs ("improve," "increase"). This is a parallelism split.

Step 3: Determine the pattern. The first item is "to reduce costs," an infinitive. For the list to be parallel, all three items must be infinitives.

Step 4: Eliminate non-parallel choices. (A) mixes "to improve" (infinitive) with "increasing" (gerund). Eliminate (A). (C) uses bare verbs "improve" and "increase" without "to," which breaks parallelism with "to reduce." Eliminate (C). (D) uses gerunds "improving" and "increasing," which break parallelism with the infinitive "to reduce." Eliminate (D).

Step 5: Compare the remaining choices. (B) uses "to improve efficiency, and to increase" and (E) uses "to improve efficiency, and increase." Both maintain the infinitive pattern. The question is whether "to" needs to be repeated before the third item. In English, the infinitive marker "to" can distribute across all items in a list: "to reduce, improve, and increase" means "to reduce, to improve, and to increase." Both (B) and (E) are grammatically correct.

Step 6: Apply concision. When two answers are both correct, the shorter one is preferred. (E) omits the second "to," which is acceptable and more concise. (B) repeats "to," which is also correct but wordier.

Correct answer: (E) to improve efficiency, and increase

Original sentence:

Unlike the previous model, the new software's interface is faster and more intuitive.

Answer choices:

(A) Unlike the previous model, the new software's (B) Unlike the previous model, the new software has an (C) Unlike the previous model's interface, the new software's (D) Unlike that of the previous model, the new software's (E) Unlike the interface of the previous model, the new software's

Analysis:

Step 1: Read the full sentence. The sentence compares the new software's interface to the previous model. The comparison needs to be between two interfaces, not between an interface and a model.

Step 2: Identify the split. The choices differ on what comes after "Unlike": "the previous model" (A, B), "the previous model's interface" (C), "that of the previous model" (D), "the interface of the previous model" (E). They also differ on the subject: "the new software's" (A, C, D, E) vs. "the new software has an" (B). This is a comparison-parallelism split.

Step 3: Check the comparison. The original sentence (A) compares "the previous model" (a product) to "the new software's interface" (a part of a product). That is illogical. You must compare interfaces to interfaces. Eliminate (A).

Step 4: Eliminate other illogical comparisons. (B) changes the structure to "the new software has an interface," but still compares "the previous model" to "the new software has an interface." That is not parallel. Eliminate (B).

Step 5: Compare the remaining choices. (C) compares "the previous model's interface" to "the new software's" (which implies "the new software's interface"). (D) compares "that of the previous model" (where "that" refers to "interface") to "the new software's." (E) compares "the interface of the previous model" to "the new software's." All three compare interface to interface.

Step 6: Check for concision and clarity. (C) uses the possessive "model's interface" which is concise and clear. (E) uses "the interface of the previous model" which is equally clear but slightly longer. (D) uses "that" as a pronoun, which works but is slightly less clear. Both (C) and (E) are correct. (C) is more concise.

Correct answer: (C) Unlike the previous model's interface, the new software's