6.4 Frequently Confused Words and Idiomatic Prepositions

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:

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

1. 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.
2. 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.