GMAT Review: Sentence Correction (Subject‑Verb Agreement, Parallelism, Modifiers, Idioms, Verb Tense)

GMAT – Sentence Correction (Subject‑Verb Agreement, Parallelism, Modifiers, Idioms, Verb Tense)

GMAT Sentence‑Correction Study Guide
Focus: Subject‑Verb Agreement, Parallelism, Modifiers, Idioms, Verb Tense

What This Is

Sentence‑Correction (SC) asks you to choose the answer that best expresses the meaning of the original sentence while obeying standard English grammar. The GMAT tests five “high‑frequency” grammar pillars—subject‑verb agreement, parallelism, modifier placement, idiomatic usage, and verb tense—because a single error can render an answer choice “incorrect.”
Typical stem: “The committee has/have/has been/has had/has having …” – you must spot the agreement error and pick the grammatically sound alternative.

Key Terms & Rules

• Subject‑Verb Agreement: The verb must match its subject in number (singular/plural) and person. Example: “Neither the data nor the analysis is convincing.”
• Collective Noun Rule: Treat a collective noun (team, committee) as singular unless the context emphasizes individual members. Example: “The board decides…,” not “decide.”
• Indefinite Pronoun Agreement: Words like each, everyone, nobody are singular; few, many, several are plural. Example: “Each of the proposals has merit.”
• Parallelism: Elements joined by and, or, nor, not only…but also must share the same grammatical form. Example: “She enjoys reading, writing, and to paint” → correct to “reading, writing, and painting.”
• Correlative Conjunctions: Both…and; either…or; neither…nor demand parallel structure on both sides.
• Misplaced Modifier: A modifier must be placed next to the word it describes; otherwise the sentence becomes ambiguous. Example: “Running quickly, the finish line was crossed by John” → correct to “Running quickly, John crossed the finish line.”
• Dangling Modifier: When the subject of the modifier is missing, the sentence is ungrammatical. Example: “After reviewing the report, the data seemed inaccurate.” → add “we” or re‑phrase.
• Idiomatic Expression: GMAT expects standard idioms (e.g., “in contrast to,” “as opposed to,” “due to”). Non‑idiomatic phrasing is a quick trap.
• Verb Tense Consistency: Keep the main verb tense consistent unless a shift is logically required (e.g., a past‑to‑present change for a timeless truth). Example: “The study found that the market is expanding.”
• Sequence of Tenses: When a subordinate clause refers to a past event, its verb should reflect that past perspective. Example: “She said that the project had been delayed.”

Step‑by‑Step Process Flow

1. Read the Stem Carefully – Identify the subject and the verb in the underlined portion; note any correlative conjunctions or modifiers.
2. Check Core Grammar – Verify subject‑verb agreement, verb tense, and idiomatic phrasing first; eliminate any choice that violates these basics.
3. Test Parallelism – Look at items linked by and/or/not only…but also. Ensure each element shares the same form; discard answers that break parallelism.
4. Locate Modifiers – Spot any adjectives, adverbs, or participial phrases; confirm they are correctly placed next to the word they modify.
5. Compare Remaining Choices – If more than one answer survives, choose the one that is most concise and maintains the original meaning without adding or omitting information.

Common Mistakes

• Mistake: Selecting an answer that “sounds right” because it contains a familiar word (e.g., “due to” vs. “because of”).
  Correction: Trust the grammar rules—due to must modify a noun, not a verb.

• Mistake: Ignoring the plural form of a collective noun when the sentence emphasizes individual actions (“The team are…”).
  Correction: Unless the context explicitly treats members separately, keep the verb singular.

• Mistake: Over‑correcting a dangling modifier by moving the phrase, but unintentionally changing the sentence’s meaning.
  Correction: Re‑write the modifier so the subject is clear and the original intent is preserved.

• Mistake: Assuming parallelism is satisfied because the words look similar (e.g., “to analyze, evaluating, and the report”).
  Correction: All items must share the same grammatical form—infinitive, gerund, or noun phrase.

• Mistake: Shifting verb tense without a logical reason (e.g., “The study shows that the market was expanding”).
  Correction: Keep the tense consistent unless the shift signals a change in time frame required by the logic.

Exam Insights

1. Most‑Tested Error: Parallelism—about 30 % of SC questions hinge on a single non‑parallel element.
2. Trap Pattern: The answer choice that adds a word (often an extra preposition) is usually wrong; the GMAT prefers the most economical phrasing.
3. Modifier Pitfall: “Misplaced modifier” choices often place a phrase at the sentence’s start; the correct answer will relocate it next to the proper noun.
4. Idioms vs. Formal Style: The GMAT favors formal idioms (“in contrast to”) over colloquial ones (“compared with”).

Quick Check Questions

1. Which answer best corrects the underlined portion?
   
   “The committee have reached a consensus, but the members disagree on implementation.”
2. A) have … but … disagree
3. B) has … but … disagrees
4. C) has … yet … disagree
5. D) has … but … disagrees
6. E) have … yet … disagrees

Answer: C – “has” matches the singular collective noun; “yet” correctly contrasts the two clauses; “disagree” stays plural because it refers to the members.

1. Identify the parallelism error:
   
   “She is praised for her diligence, her ability to lead, and being a great communicator.”
2. A) No error
3. B) Replace “being a great communicator” with “her great communication skills”
4. C) Change “ability to lead” to “leading”
5. D) Change “diligence” to “being diligent”

Answer: B – All three items must be noun phrases; “being a great communicator” is a gerund phrase, breaking parallelism.

1. Verb‑tense consistency:
   
   “The analyst predicted that the market will experience a downturn, which has already begun.”
2. A) No error
3. B) Change “will” to “would”
4. C) Change “has” to “had”
5. D) Change “predicted” to “predicts”

Answer: B – The main clause is past (“predicted”), so the subordinate future must be backshifted to “would.”

Last‑Minute Cram Sheet

1. ⚠️ Subject‑Verb Agreement: Singular subjects → singular verbs; collective nouns stay singular unless “each member” is emphasized.
2. Parallelism Rule: Items linked by and/or/not only…but also must share the same grammatical form.
3. Correlative Conjunctions demand parallel structure on both sides.
4. Misplaced Modifier: Place the modifier immediately before/after the word it describes.
5. Dangling Modifier Fix: Add the missing subject or re‑write the clause.
6. Idiomatic Preference: Use “in contrast to,” “as opposed to,” “due to,” not informal equivalents.
7. Verb Tense Consistency: Keep the main verb tense steady; only shift when a logical time change is required.
8. Sequence of Tenses: Past‑time reporting verbs → past perfect in subordinate clause if the action preceded the reporting.
9. Conciseness Principle: The correct answer is the most concise phrasing that preserves meaning.
10. ⚠️ Trap Alert: The answer that adds a preposition or extra word is rarely the right choice on the GMAT.