Sentence Structure and usage errors

Table of Contents
1. Complete Sentences vs. Fragments and Run-Ons
2. Subject-Verb Agreement
3. Pronoun-Antecedent Agreement
4. Verb Tense Consistency and Usage
5. Pronoun Case
6. Modifier Placement
7. Parallelism
8. Coordination and Subordination
9. Wordiness and Redundancy
10. Sentence Logic and Clarity
11. Idioms and Standard Expressions
12. Commonly Confused Words
13. Adjective and Adverb Usage
View more

Sentence structure and usage form the backbone of clear, effective writing. These questions test your ability to identify and fix errors in how sentences are built and how words function together. You'll need to recognize grammatical mistakes, awkward constructions, and violations of standard written English. This section focuses on practical error recognition and correction-understanding just enough theory to spot problems quickly and fix them accurately.

1. Complete Sentences vs. Fragments and Run-Ons

Every correct sentence needs two essential parts: a subject (who/what performs the action) and a predicate (the action or state of being). Missing either creates a fragment; jamming multiple sentences together incorrectly creates a run-on.

1.1 Sentence Fragments

A fragment is an incomplete sentence pretending to be complete. It lacks a subject, a verb, or doesn't express a complete thought.

• Missing Subject: "Ran to the store quickly." (Who ran? Subject missing)
• Missing Verb: "The students in the library." (What about them? Verb missing)
• Dependent Clause Alone: "Because she was tired." (This starts with 'because'-needs a main clause)
• Phrase Fragment: "Walking down the street." (No subject performing a complete action)

How to Fix Fragments:

1. Add the missing subject or verb: "She ran to the store quickly."
2. Attach to nearby complete sentence: "She went home early because she was tired."
3. Remove subordinating word: "She was tired." (Remove 'because')

Common Trap: Starting a sentence with subordinating conjunctions (because, although, while, if, when, since) often creates fragments unless you include both dependent AND independent clauses.

1.2 Run-On Sentences

A run-on occurs when two or more independent clauses are joined incorrectly without proper punctuation or conjunctions.

• Fused Sentence: "She loves reading she visits the library weekly." (Two complete sentences mashed together)
• Comma Splice: "She loves reading, she visits the library weekly." (Comma alone cannot join two independent clauses)

How to Fix Run-Ons (4 Methods):

1. Period: "She loves reading. She visits the library weekly."
2. Semicolon: "She loves reading; she visits the library weekly."
3. Comma + Coordinating Conjunction: "She loves reading, so she visits the library weekly." (FANBOYS: for, and, nor, but, or, yet, so)
4. Subordination: "Because she loves reading, she visits the library weekly."

Common Trap: Words like "however," "therefore," "moreover," and "consequently" are NOT coordinating conjunctions. They need a semicolon or period before them: "She studied hard; however, she still felt nervous."

2. Subject-Verb Agreement

The subject and verb must match in number (singular/plural). Singular subjects take singular verbs; plural subjects take plural verbs.

2.1 Basic Agreement Rules

• Singular: "The dog runs fast." (One dog = singular verb 'runs')
• Plural: "The dogs run fast." (Multiple dogs = plural verb 'run')
• He/She/It Rule: Add 's' to verb for third-person singular: "She walks," not "She walk"

2.2 Tricky Agreement Situations

Intervening Phrases: Words between subject and verb don't affect agreement.

• Wrong: "The list of items are on the desk." (Subject is 'list,' not 'items')
• Right: "The list of items is on the desk."
• Tip: Cross out prepositional phrases (of items, in the box, with friends) to find the true subject.

Compound Subjects:

• AND = Plural: "Tom and Jerry are friends." (Two subjects = plural)
• OR/NOR = Match Closer Subject: "Neither the teacher nor the students are ready." (Students is closer and plural)
• OR/NOR = Match Closer Subject: "Neither the students nor the teacher is ready." (Teacher is closer and singular)

Indefinite Pronouns:

• Always Singular: each, either, neither, one, everyone, everybody, anyone, anybody, someone, somebody, no one, nobody → "Everyone is present."
• Always Plural: both, few, many, several → "Few are selected."
• Context-Dependent: all, some, most, none (depends on the noun) → "Some of the cake is eaten." vs. "Some of the cookies are eaten."

Inverted Word Order: When subject comes after verb, identify subject carefully.

• "There are three books on the table." (Subject is 'books,' not 'there')
• "Here is the solution." (Subject is 'solution')

Collective Nouns: Group words (team, family, committee, jury) are usually singular in American English.

• "The team is winning." (Team acts as one unit)
• "The team are arguing among themselves." (Rare: when emphasizing individual members)

Common Trap: Don't be fooled by plural-looking words that are singular: news, mathematics, physics, economics → "The news is shocking."

3. Pronoun-Antecedent Agreement

A pronoun must agree with its antecedent (the noun it replaces) in number (singular/plural), gender (male/female/neutral), and person (first/second/third).

3.1 Number Agreement

• Singular Antecedent = Singular Pronoun: "Each student must bring his or her textbook." (Not 'their'-'each' is singular)
• Plural Antecedent = Plural Pronoun: "The students must bring their textbooks."
• Wrong: "A person should follow their dreams." (Person is singular)
• Right: "A person should follow his or her dreams." OR "People should follow their dreams."

3.2 Indefinite Pronoun Agreement

• Singular Indefinites: everyone, everybody, someone, somebody, anyone, anybody, each, either, neither → "Everyone should do his or her homework."
• Common Trap: "Everybody brought their lunch." (Wrong on formal tests-'everybody' is singular)
• Correct: "Everybody brought his or her lunch."

3.3 Compound Antecedents

• AND = Plural Pronoun: "Sarah and Mike finished their project."
• OR/NOR = Match Closer Antecedent: "Neither the boys nor Maria brought her permission slip."

3.4 Ambiguous Pronoun Reference

A pronoun must clearly refer to ONE specific antecedent. Avoid vague references.

• Unclear: "When Sarah told Michelle about the problem, she was upset." (Who was upset? Sarah or Michelle?)
• Clear: "When Sarah told Michelle about the problem, Michelle was upset."
• Unclear: "The coach discussed the game with the team before it began." (What began? The discussion or the game?)
• Clear: "Before the game began, the coach discussed it with the team."

Vague "This," "That," "Which," "It":

• Wrong: "I studied all night and still failed. This was disappointing." (What does 'this' refer to?)
• Right: "I studied all night and still failed. This result was disappointing."

4. Verb Tense Consistency and Usage

Maintain logical verb tense throughout a sentence or passage. Shift tenses only when the timeline actually changes.

4.1 Consistent Tense

• Wrong: "She walks to the store and bought milk." (Shifts from present 'walks' to past 'bought')
• Right: "She walked to the store and bought milk." (Both past)
• Right: "She walks to the store and buys milk." (Both present)

4.2 Logical Tense Shifts

Change tenses when the time actually changes.

• Correct Shift: "She studied hard yesterday, so she is confident today." (Past action, present feeling)
• Correct Shift: "By the time we arrived, the movie had started." (Past perfect for earlier past action)

4.3 Sequence of Tenses

Present Perfect vs. Simple Past:

• Present Perfect: "I have lived here for five years." (Started in past, continues now)
• Simple Past: "I lived there for five years." (Completed action, no longer live there)

Past Perfect for Earlier Past Action:

• Wrong: "She realized she forgot her keys." (Both simple past-unclear sequence)
• Right: "She realized she had forgotten her keys." (Forgetting happened before realizing)

Future in the Past:

• "He said he would call later." (Not 'will call'-reporting past statement about future)

Common Trap: "Since" requires perfect tense: "Since I have been here, I learned a lot." (Wrong) → "Since I have been here, I have learned a lot." (Correct)

5. Pronoun Case

Pronouns change form based on their function in a sentence. Use the correct case.

5.1 Three Cases

• Subjective (Subject): I, you, he, she, it, we, they, who → "She and I went to school."
• Objective (Object): me, you, him, her, it, us, them, whom → "The teacher called her and me."
• Possessive: my, mine, your, yours, his, her, hers, its, our, ours, their, theirs, whose → "Their house is large."

5.2 Common Case Errors

Compound Subjects/Objects: Test by removing the other person.

• Wrong: "John and me went shopping." (Test: "Me went shopping"-sounds wrong)
• Right: "John and I went shopping." (Test: "I went shopping"-correct)
• Wrong: "The gift was for Sarah and I." (Test: "for I"-sounds wrong)
• Right: "The gift was for Sarah and me." (Test: "for me"-correct)

After Prepositions (between, with, for, to, from): Always use objective case.

• Wrong: "Between you and I..."
• Right: "Between you and me..."
• Wrong: "The task was divided among we students."
• Right: "The task was divided among us students."

Who vs. Whom:

• Who (Subject): "Who called?" (He called → subject)
• Whom (Object): "Whom did you call?" (You called him → object)
• Trick: Replace with he/him. If "him" fits, use "whom"; if "he" fits, use "who".

Than/As Comparisons: Choose case based on implied meaning.

• "She likes him more than I [do]." (I like him-subjective)
• "She likes him more than [she likes] me." (She likes me-objective)

5.3 Possessive Pronouns vs. Contractions

• Its (possessive): "The dog wagged its tail." (No apostrophe for possession)
• It's (contraction): "It's a beautiful day." (It is)
• Your (possessive): "Your book is here."
• You're (contraction): "You're doing well." (You are)
• Their (possessive): "Their house."
• They're (contraction): "They're coming." (They are)
• Whose (possessive): "Whose bag is this?"
• Who's (contraction): "Who's there?" (Who is)

Common Trap: Possessive pronouns NEVER use apostrophes: its, yours, hers, ours, theirs.

6. Modifier Placement

Modifiers (words or phrases that describe) must be placed next to what they describe. Misplaced or dangling modifiers create confusion or unintended humor.

6.1 Misplaced Modifiers

A misplaced modifier is too far from what it modifies, creating confusion.

• Wrong: "She served sandwiches to the children on paper plates." (Were children on plates?)
• Right: "She served sandwiches on paper plates to the children."
• Wrong: "I saw a dog riding my bike." (Dog riding bike?)
• Right: "Riding my bike, I saw a dog."

Limiting Modifiers: Words like "only," "almost," "nearly," "just," "even" must be placed immediately before the word they modify.

• "I only ate vegetables." (Didn't do anything else-just ate)
• "I ate only vegetables." (Ate nothing but vegetables)
• "She almost failed every test." (Came close to failing but didn't)
• "She failed almost every test." (Failed most tests, not all)

6.2 Dangling Modifiers

A dangling modifier describes something that isn't actually in the sentence. The subject being modified is missing.

• Wrong: "Walking to school, the rain started." (Rain isn't walking)
• Right: "Walking to school, I noticed the rain started." (Add the subject 'I')
• Wrong: "After studying all night, the test was easy." (Test didn't study)
• Right: "After studying all night, I found the test easy."
• Wrong: "To win the race, practice is essential." (Practice can't win)
• Right: "To win the race, you must practice." OR "To win the race, one must practice."

Fix Strategy: The subject immediately after the introductory phrase must be the one performing the action in that phrase.

6.3 Squinting Modifiers

A squinting modifier is positioned where it could modify either what comes before or after it.

• Unclear: "Students who study often get good grades." (Study often? Or often get good grades?)
• Clear: "Students who often study get good grades." OR "Often, students who study get good grades."

7. Parallelism

Parallelism means using the same grammatical structure for items in a list or comparison. Balanced structures improve clarity and readability.

7.1 Lists and Series

Items in a series must have matching grammatical forms.

• Wrong: "She likes reading, to swim, and jogging." (Gerund, infinitive, gerund-not parallel)
• Right: "She likes reading, swimming, and jogging." (All gerunds)
• Right: "She likes to read, to swim, and to jog." (All infinitives)

7.2 Correlative Conjunctions

These paired conjunctions require parallel structures: either...or, neither...nor, not only...but also, both...and.

• Wrong: "She is not only intelligent but also has creativity." (Adjective + verb phrase-not parallel)
• Right: "She is not only intelligent but also creative." (Both adjectives)
• Wrong: "You can either study now or fail later." (Verb after 'either' but verb after 'or'-actually parallel, but clearer if...)
• Better: "Either study now or fail later." (Verb + verb directly after conjunctions)

7.3 Comparisons

Compare items in the same grammatical form.

• Wrong: "Swimming is more exhausting than to run." (Gerund vs. infinitive)
• Right: "Swimming is more exhausting than running." (Both gerunds)
• Wrong: "The new policy is better than the old one was." (Incomplete comparison)
• Right: "The new policy is better than the old one."

7.4 Parallel Structure in Clauses

• Wrong: "The coach told us to practice daily and that we should focus." (Infinitive vs. clause)
• Right: "The coach told us to practice daily and to focus." (Both infinitives)
• Right: "The coach told us that we should practice daily and that we should focus." (Both clauses)

Common Trap: Watch for lists or comparisons that start with one structure then switch midway. Keep all elements matching.

8. Coordination and Subordination

Effective sentences show the relationship between ideas through proper coordination (equal ideas) or subordination (one idea dependent on another).

8.1 Coordination

Coordinating conjunctions (FANBOYS: for, and, nor, but, or, yet, so) join equal, independent clauses.

• Example: "I wanted to go, but I was too tired." (Two equal statements)
• Example: "She studied hard, so she passed the exam." (Cause and effect, both important)

Wrong Coordination: Don't join unrelated or unequal ideas with coordination.

• Weak: "The weather was nice, and I ate breakfast." (Random connection)
• Better: Use two separate sentences OR find actual connection.

8.2 Subordination

Subordinating conjunctions show one clause depends on another. Common ones: although, because, since, while, if, when, unless, until, whereas, after, before.

• Example: "Because she studied hard, she passed." (Dependent clause + independent clause)
• Example: "She passed because she studied hard." (Independent clause + dependent clause)

Showing Proper Relationships:

• Weak: "She was tired, and she went to bed." (Makes equal-but cause-effect is clearer)
• Better: "Because she was tired, she went to bed." (Shows reason clearly)

Common Trap: Starting a subordinate clause makes it incomplete. Must attach to independent clause or it's a fragment.

8.3 Choosing Between Coordination and Subordination

• Equal Importance: Use coordination → "I like tea, and she likes coffee."
• One Idea More Important: Use subordination → "Although I like tea, I'm drinking coffee today." (Focus on drinking coffee today)
• Cause-Effect: Use subordination → "Since it was raining, we stayed inside."

9. Wordiness and Redundancy

Strong writing is concise. Eliminate unnecessary words without losing meaning.

9.1 Common Wordy Phrases

• Wordy: "at this point in time" → Concise: "now"
• Wordy: "due to the fact that" → Concise: "because"
• Wordy: "in spite of the fact that" → Concise: "although"
• Wordy: "in the event that" → Concise: "if"
• Wordy: "has the ability to" → Concise: "can"
• Wordy: "make a decision" → Concise: "decide"
• Wordy: "come to a conclusion" → Concise: "conclude"

9.2 Redundant Expressions

Avoid saying the same thing twice with different words.

• Redundant: "advance planning" → Concise: "planning" (all planning is in advance)
• Redundant: "past history" → Concise: "history" (history is always past)
• Redundant: "end result" → Concise: "result"
• Redundant: "close proximity" → Concise: "proximity"
• Redundant: "completely eliminate" → Concise: "eliminate"
• Redundant: "absolutely essential" → Concise: "essential"
• Redundant: "free gift" → Concise: "gift" (gifts are free)

9.3 Passive Voice Wordiness

Active voice is usually clearer and more concise than passive.

• Passive/Wordy: "The ball was thrown by Sarah." (6 words)
• Active/Concise: "Sarah threw the ball." (4 words)
• Passive/Wordy: "Mistakes were made by the committee."
• Active/Concise: "The committee made mistakes."

Note: Passive voice is acceptable when the doer is unknown or unimportant: "The package was delivered yesterday." (We don't know/care who delivered it)

10. Sentence Logic and Clarity

10.1 Faulty Comparison

Comparisons must be between similar, logical items.

• Wrong: "New York's population is larger than Chicago." (Comparing population to city)
• Right: "New York's population is larger than Chicago's [population]."
• Wrong: "My car is faster than John." (Comparing car to person)
• Right: "My car is faster than John's [car]."
• Wrong: "This phone's features are better than any phone." (Can't be better than itself)
• Right: "This phone's features are better than those of any other phone."

10.2 Mixed Construction

A sentence starts with one structure and switches to another incompatible structure midway.

• Wrong: "By exercising regularly is how you stay healthy." (Prepositional phrase can't be subject)
• Right: "Exercising regularly is how you stay healthy." OR "You stay healthy by exercising regularly."
• Wrong: "The reason she left is because she was tired." ('Reason...is because' is redundant)
• Right: "The reason she left is that she was tired." OR "She left because she was tired."
• Wrong: "Just because you're older doesn't mean you're wiser." (Common in speech, wrong in writing)
• Right: "You're not necessarily wiser just because you're older."

10.3 Faulty Predication

The subject and predicate must make logical sense together.

• Wrong: "The function of the heart circulates blood." (Functions don't circulate; hearts do)
• Right: "The heart circulates blood." OR "The function of the heart is to circulate blood."
• Wrong: "The chapter says that..." (Chapters don't speak)
• Right: "The author says in the chapter..." OR "The chapter discusses..."

11. Idioms and Standard Expressions

Certain phrases have fixed, correct forms. Use the right prepositions and word combinations.

11.1 Common Preposition Idioms

• Different from: "This is different from that." (Not 'different than')
• Regard as: "I regard him as a friend." (Not 'regard to be')
• Think of/about: "I'm thinking of you." / "Think about the consequences."
• Worried about: "She's worried about the exam." (Not 'worried of')
• Prohibit from: "They prohibit students from using phones." (Not 'prohibit to use')
• Subscribe to: "I subscribe to that magazine."
• Agree with (person)/on (topic)/to (proposal): Context matters

11.2 Fixed Expressions

• Between...and: "between 5 and 10" (Not 'between 5 to 10')
• Both...and: "both smart and funny" (Not 'both smart as well as funny')
• As...as: "She is as tall as her brother." (Not 'as tall like')
• So...that: "It was so hot that we stayed inside." (Not 'so hot where')
• Scarcely/Hardly...when: "I had scarcely arrived when it started raining." (Not 'scarcely...than')

Common Trap: Mixing idioms: "She is as tall or taller than him" (Missing 'as' after tall). Correct: "She is as tall as or taller than him." OR "She is as tall as him or taller."

12. Commonly Confused Words

12.1 Accept vs. Except

• Accept (verb): to receive or agree → "I accept your apology."
• Except (preposition): excluding → "Everyone came except John."

12.2 Affect vs. Effect

• Affect (verb): to influence → "The weather affects my mood."
• Effect (noun): a result → "The effect was immediate."
• Effect (verb - rare): to bring about → "The new law will effect change."

12.3 Than vs. Then

• Than (comparison): "She is taller than me."
• Then (time/sequence): "We ate, then we left."

12.4 Lay vs. Lie

• Lay (transitive - needs object): to put/place something → "I lay the book on the table." (Present: lay, Past: laid, Past Participle: laid)
• Lie (intransitive - no object): to recline → "I lie down to rest." (Present: lie, Past: lay, Past Participle: lain)
• Common Error: "I'm going to lay down." (Wrong - use 'lie') → "I'm going to lie down."

12.5 Amount vs. Number

• Amount (uncountable): "a large amount of water"
• Number (countable): "a large number of students"

12.6 Less vs. Fewer

• Less (uncountable): "less water"
• Fewer (countable): "fewer students"

12.7 Among vs. Between

• Between (two items): "Divide it between Sarah and Tom."
• Among (three or more): "Divide it among the five students."

13. Adjective and Adverb Usage

13.1 Adjective vs. Adverb

Adjectives modify nouns/pronouns. Adverbs modify verbs, adjectives, or other adverbs.

• Adjective: "She is a quick runner." (Describes 'runner,' a noun)
• Adverb: "She runs quickly." (Describes 'runs,' a verb)
• Wrong: "She did good on the test." ('Good' is adjective; can't modify verb 'did')
• Right: "She did well on the test." ('Well' is adverb)

13.2 After Linking Verbs

Linking verbs (be, seem, appear, feel, look, smell, taste, sound, become, remain) connect subject to description. Use adjectives, not adverbs, after linking verbs.

• Right: "The soup tastes delicious." (Adjective describing soup, not how it tastes)
• Wrong: "The soup tastes deliciously."
• Right: "She feels bad about the mistake." (Adjective describing her state)
• Wrong: "She feels badly." (Would mean her sense of touch is impaired)
• Right: "The music sounds beautiful."

13.3 Comparative and Superlative Forms

Comparative (comparing two): Use -er or 'more'

• "She is taller than her sister."
• "This task is more difficult than that one."

Superlative (comparing three or more): Use -est or 'most'

• "She is the tallest in the class."
• "This is the most difficult task."

Common Errors:

• Double Comparison: "more better" (Wrong) → "better" (Correct)
• Wrong Degree: "Between the two, he is strongest." (Wrong - only two, use comparative) → "Between the two, he is stronger."
• Irregular Forms: good/better/best, bad/worse/worst, many-much/more/most, little/less/least

Understanding sentence structure and usage errors gives you the power to spot mistakes quickly and fix them correctly. Practice identifying error patterns, test answer choices by reading them aloud mentally, and trust your ear for what sounds right-but verify with these rules. Most questions reward careful attention to subject-verb agreement, pronoun issues, and modifier placement. Master these core concepts, and you'll handle sentence structure questions with confidence.