6.4 Frequently Confused Words and Idiomatic Prepositions

ACCUPLACER Writing Study Guide Exam

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1 Introduction & ACCUPLACER Writing Overview

1.1 About the ACCUPLACER Writing Test 1.2 Test-Taking Strategies & Passage-Based Revision

2 Expression of Ideas: Development

2.1 Proposition, Thesis Statements, and Topic Sentences 2.2 Supporting Details, Evidence, and Textual Relevance 2.3 Audience, Rhetorical Purpose, and Essay Focus

3 Expression of Ideas: Organization

3.1 Logical Sentence and Paragraph Sequence 3.2 Transitional Words and Cohesive Devices 3.3 Effective Introductions, Conclusions, and Summary Sentences

4 Expression of Ideas: Effective Language Use

4.1 Precision and Contextual Vocabulary 4.2 Concision and Eliminating Redundancy 4.3 Style, Tone, and Formal Academic Diction 4.4 Sentence Combination, Syntactic Variety, and Structure

5 Standard English Conventions: Sentence Structure

5.1 Sentence Fragments, Run-Ons, and Comma Splices 5.2 Parallel Structure in Lists and Compound Elements 5.3 Misplaced, Dangling, and Illogical Modifiers 5.4 Subordination, Coordination, and Clause Relationships

6 Standard English Conventions: Conventions of Usage

6.1 Subject-Verb Agreement 6.2 Pronoun Agreement, Antecedent Clarity, and Pronoun Case 6.3 Verb Tense, Sequence, and Aspect 6.4 Frequently Confused Words and Idiomatic Prepositions

7 Standard English Conventions: Conventions of Punctuation

7.1 End-of-Sentence Punctuation and Comma Rules 7.2 Semicolons, Colons, and Dashes 7.3 Apostrophes, Possessives, and Quotation Marks

6.4 Frequently Confused Words and Idiomatic Prepositions

Key Takeaways Explain This Topic AI

Homophones (words that sound alike but have different meanings and spellings) are frequently tested; mastering the distinction between pairs like affect/effect and its/it's is crucial.

'Affect' is almost always a verb meaning to influence, while 'effect' is almost always a noun meaning a result.

Idioms in English do not follow strict logical rules; they are customary pairings of words, particularly verbs or adjectives paired with specific prepositions (e.g., 'capable of' not 'capable to').

When encountering a preposition question, rely on your ear and reading experience, as idiomatic pairings must be memorized.

Last updated: July 2026

Navigating Usage Conventions

Beyond structural grammar, the ACCUPLACER tests your knowledge of standard English vocabulary usage. This primarily involves distinguishing between words that sound similar but mean different things (frequently confused words) and using the correct preposition to accompany certain verbs or adjectives (idioms).

Frequently Confused Words (Homophones)

Test writers love homophones because relying solely on how a sentence "sounds" will not help you; you must know the definitions and spellings. Below is a list of the most commonly tested pairs.

Affect vs. Effect

This is perhaps the most heavily tested pair on the exam.

Affect is a VERB meaning to influence or to produce a change in. (Action = Affect).

Example: The severe weather will affect the crop yields.

Effect is a NOUN meaning a result, a consequence, or an outcome. (The Effect).

Example: The severe weather had a devastating effect on the crop yields. (Note: Rarely, 'effect' is a verb meaning 'to bring about' as in "effect change," but this is almost never tested).

Its vs. It's

Its is the possessive form of "it." It shows ownership. (Note the lack of an apostrophe, just like "his" or "hers").

Example: The company updated its privacy policy.

It's is a contraction for "it is" or "it has."

Example: It's going to rain tomorrow. (Strategy: Always read "it's" as "it is" in your head. If "it is" makes sense, use the apostrophe. If not, use "its.")

Than vs. Then

Than is used for comparisons .

Example: The first version was much faster than the second.

Then is used to indicate time or sequence (what happens next).

Example: We finished the report, and then we went home.

Their vs. There vs. They're

Their is possessive , meaning belonging to them.

Example: The students submitted their essays.

There refers to a place or is used as a structural filler (e.g., "There are...").

Example: Please place the package over there .

They're is a contraction for "they are."

Example: They're planning to announce the merger tomorrow.

• Principal vs. Principle
• Principal refers to a school administrator, a sum of money, or means "main" or "primary."

Example: The principal reason for the delay was poor weather.

Principle is a fundamental truth, law, or rule.

Example: The country was founded on the principle of liberty.

Compliment vs. Complement

Compliment is a flattering remark or praise.

Example: She received a nice compliment on her presentation.

Complement means to complete, enhance, or make perfect.

Example: The bold tie perfectly complements the suit.

Idiomatic Prepositions

In standard English, certain verbs and adjectives must be paired with specific prepositions. These pairings are called idioms. There is no grammatical rule that explains why we say "capable of " instead of "capable to "—it is simply customary usage.

The ACCUPLACER tests these idiomatic prepositions by offering an incorrect preposition and asking you to identify the correct one. Because there are no rules to memorize, you must rely on your familiarity with standard English phrasing.

Common Idiomatic Pairings

Here is a list of frequently tested idiomatic phrases:

• Word Correct Preposition Incorrect Variation
• Accused of (Accused of a crime) Accused with
• Capable of (Capable of winning) Capable to
• Comply with (Comply with the rules) Comply to
• Consistent with (Consistent with the data) Consistent to
• Familiar with (Familiar with the subject) Familiar of
• Interested in (Interested in learning) Interested about
• Object to (Object to the proposal) Object against
• Preoccupied with (Preoccupied with work) Preoccupied by/about
• Responsible for (Responsible for the error) Responsible of
• Similar to (Similar to the original) Similar with
• Idioms with Infinitives vs. Gerunds

Another type of idiom question tests whether a word should be followed by an infinitive (to + verb) or a preposition + gerund (verb ending in -ing).

• Succeed in [doing]: She succeeded in passing the test. (Not: succeeded to pass)
• Hesitate to [do]: Please do not hesitate to contact me. (Not: hesitate in contacting)
• Attempt to [do]: He made an attempt to climb the mountain. (Not: attempt of climbing)
• Strategy for Usage Questions

For Confused Words: Memorize the definitions of the most common pairs. When you see "affect/effect" or "its/it's" as answer choices, immediately define them mentally before looking at the sentence context.

For Prepositions: Read the sentence silently but "loudly" in your head. Native speakers and avid readers often have an intuitive sense of which preposition sounds correct. If you are stuck, eliminate the prepositions that sound blatantly unnatural and choose from the remaining options based on what feels most customary in formal writing.