10 HESI A2 Grammar Rules You Need to Know
The HESI A2 Grammar section tests your ability to recognize and correct errors in standard written English. Instead of memorizing every grammar exception, begin with the rules that commonly affect sentence clarity and correctness.
1. Subject-verb agreement
A singular subject generally takes a singular verb, while a plural subject takes a plural verb.
- Correct: The nursing student studies every evening.
- Correct: The nursing students study every evening.
Ignore words between the subject and verb. In “The collection of notes is organized,” collection is the singular subject.
2. Pronoun-antecedent agreement
A pronoun must agree with the noun it replaces in number and person.
- Correct: The students submitted their applications.
- Correct: Each student submitted an application.
Make sure the pronoun clearly refers to a specific noun.
3. Apostrophes
Use apostrophes to show possession or form contractions—not to make ordinary nouns plural.
- Singular possession: The nurse’s notes
- Plural possession: The nurses’ station
- Irregular plural possession: The children’s clinic
- Contraction: It’s time to begin.
Its shows possession, while it’s means “it is” or “it has.”
4. Complete sentences
A complete sentence expresses a complete thought and contains a subject and predicate.
- Fragment: Because the patient was tired.
- Complete: The patient rested because she was tired.
A run-on occurs when independent clauses are joined incorrectly. Use a period, semicolon, or comma with a coordinating conjunction.
5. Comma use
Use commas to separate items in a series, follow an introductory element, and join independent clauses with coordinating conjunctions.
- The student reviewed anatomy, biology, and chemistry.
- Before the exam, she ate breakfast.
- She understood the rule, but she still practiced it.
Do not insert a comma between a subject and its verb.
6. Adjectives and adverbs
Adjectives modify nouns or pronouns. Adverbs usually modify verbs, adjectives, or other adverbs.
- The careful student read the question.
- The student read the question carefully.
7. Consistent verb tense
Keep verb tense consistent unless the timing of an action changes.
- Incorrect: She reviewed the chapter and answers the questions.
- Correct: She reviewed the chapter and answered the questions.
8. Commonly confused words
Review word pairs that sound similar or have related meanings:
- Affect: Usually a verb meaning to influence
- Effect: Usually a noun meaning a result
- Then: Refers to time or sequence
- Than: Introduces a comparison
- There: Refers to a place
- Their: Shows possession
- They’re: Means “they are”
- Your: Shows possession
- You’re: Means “you are”
9. Capitalization
Capitalize the first word of a sentence, proper nouns, official titles used before names, days, months, and specific geographic locations.
Do not capitalize common nouns merely because they seem important.
10. Parallel structure
Items in a series should follow the same grammatical pattern.
- Incorrect: Her plan included studying, practice questions, and to review notes.
- Correct: Her plan included studying, answering practice questions, and reviewing notes.
Practice recognizing grammar errors
For each practice question, identify the exact rule being tested. Then explain why each incorrect option violates that rule. This builds knowledge you can transfer to new sentences.
Practice for the HESI A2 with Pocket Prep and learn from detailed explanations for correct and incorrect answers.
