Grammar & Usage

📝 Subject-Verb Agreement

Part 1 of 7 — Tricky Subjects, Prepositional Phrases & Compound Subjects

The ACT English section frequently tests whether you can match a subject to its verb in number (singular or plural). The trick is that the ACT hides the true subject behind extra words.

The Core Rule: A singular subject takes a singular verb; a plural subject takes a plural verb.

Why it matters on the ACT: Subject-verb agreement shows up regularly in the Conventions of Standard English questions on the 50-question English test, which makes it one of the highest-yield grammar topics you can study.

Tricky Subjects & Prepositional Phrases

The ACT loves to insert a prepositional phrase between the subject and verb to confuse you.

Strategy: Cross out the prepositional phrase to find the real subject.

Example 1 — Prepositional Phrase Trap:

• ❌ The bouquet of roses were beautiful.
• ✅ The bouquet of roses was beautiful.
• The subject is bouquet (singular), not roses.

Example 2 — Long Interruption:

• ❌ The results of the experiment, which was conducted over several months, shows a clear trend.
• ✅ The results of the experiment, which was conducted over several months, show a clear trend.
• The subject is results (plural).

Example 3 — Compound Prepositional Phrase:

• ❌ The box of chocolates on the table near the flowers have been opened.
• ✅ The box of chocolates on the table near the flowers has been opened.
• The subject is box (singular). Everything from "of" to "flowers" is extra.

ACT Tip: When you see a verb underlined, immediately find the subject. Ignore everything between commas, and cross out prepositional phrases mentally.

Subject-Verb Agreement — Spot the Error 🔍

Compound Subjects & Special Cases

Compound subjects joined by "and" are usually plural:

• Tom and Jerry are coming. ✅

Subjects joined by "or" / "nor" — the verb agrees with the nearer subject:

• Neither the teacher nor the students were ready. ✅
• Neither the students nor the teacher was ready. ✅

Indefinite pronouns — always singular:

• Everyone, somebody, each, either, neither, nobody, anything
• Each of the students has a textbook. ✅
• Everyone is welcome. ✅

Collective nouns (team, group, jury, family) are usually singular in American English:

• The committee has reached a decision. ✅

"Data": Current standard usage accepts both The data show a trend and The data shows a trend, so don't count either verb as an error. Look for a clearer agreement problem instead.

ACT Tip: "Each" and "every" always signal a singular verb, even when followed by a compound phrase: Each boy and girl has a seat.

Fill in the Correct Verb ✏️

1. "The group of scientists _____ (is/are) publishing a new study." — Type the correct verb.

2. "Neither the coach nor the players _____ (was/were) satisfied." — Type the correct verb.

3. "Everybody in the two classes _____ (has/have) finished the test." — Type the correct verb.

Quick-Check: Agreement Rules 🔍

ACT-Style Practice 📋

🗣️ Pronoun Usage

Part 2 of 7 — Agreement, Case, Ambiguous Reference & Who/Whom

Pronoun questions are a staple of ACT English. The test checks three things:

1. Agreement — Does the pronoun match its antecedent in number?
2. Case — Is the pronoun in the right form (subject vs. object)?
3. Clarity — Is it clear what the pronoun refers to?

Pronoun-Antecedent Agreement

A pronoun must agree with its antecedent (the noun it replaces) in number and gender.

Example 1 — Singular Antecedent (a thing):

• ❌ The bridge was closed because they needed repairs.
• ✅ The bridge was closed because it needed repairs.
• A single object takes a singular pronoun. This kind of clear number mismatch is what the ACT tests.

A note on singular "they": When the antecedent is a generic person (a student, someone, each driver), both forms are acceptable in current standard English and ACT style:

• ✅ A student should always bring his or her textbook to class.
• ✅ A student should always bring their textbook to class.
• Don't mark singular "they" wrong. If an answer choice rewrites the whole sentence in the plural (Students should bring their textbooks), that is fine too.

Example 2 — Plural Antecedent:

• ❌ The musicians tuned his instruments before the concert.
• ✅ The musicians tuned their instruments before the concert.

Example 3 — Collective Noun:

• ✅ The jury reached its verdict. (American English treats collective nouns as singular.)

ACT Tip: When a pronoun is underlined, immediately find the antecedent. Check: Does the pronoun match in number? If not, that's the error.

Pronoun Agreement — Identify the Error 🔍

Pronoun Case: Subject vs. Object

Use subject pronouns (I, he, she, we, they, who) as subjects or after linking verbs. Use object pronouns (me, him, her, us, them, whom) as objects of verbs or prepositions.

Example 4 — Compound Subject:

• ❌ Me and Sarah went to the store.
• ✅ Sarah and I went to the store.
• Test: Remove "Sarah and" — "I went to the store" ✅; "Me went to the store" ❌.

Example 5 — Object of Preposition:

• ❌ The teacher gave the award to Sarah and I.
• ✅ The teacher gave the award to Sarah and me.
• Test: Remove "Sarah and" — "gave the award to me" ✅; "gave the award to I" ❌.

Who vs. Whom:

• Who = subject (like "he"): Who is calling? → He is calling.
• Whom = object (like "him"): To whom did you speak? → You spoke to him.
• Set aside inserted clauses first. Phrases like I think, we know, or the judges believe don't change the pronoun's job. In The singer (who / whom) the judges believe will win, cross out "the judges believe": who will win → she will win, so who is correct. Running the he/him swap on "the judges believe ___" would wrongly point to "whom."

ACT Tip: For compound pronoun questions, mentally remove the other person. "Give it to (she / her) and me" → "Give it to her" ✅.

Choose the Correct Pronoun ✏️

1. "Between you and _____ (I/me), this test is difficult." — Type the correct pronoun.

2. "_____ (Who/Whom) did the principal call to the office?" — Type the correct word.

3. "The trophy belongs to my teammates and _____ (I/me)." — Type the correct pronoun.

Pronoun Rules — Quick Check 🔍

ACT-Style Practice 📋

⏳ Verb Tense Consistency

Part 3 of 7 — Tense Shifts, Perfect Tenses & Sequence of Events

The ACT tests whether you can keep verb tenses consistent within a sentence and across a passage. Unnecessary tense shifts are one of the most common errors tested.

The Golden Rule: Don't shift tenses unless there's a reason (a time change, a shift from general truth to specific event, etc.).

Unnecessary Tense Shifts

A tense shift is an error when the time frame hasn't changed but the verb tense does.

Example 1 — Unnecessary Shift:

• ❌ She opened the door and sees a package on the porch.
• ✅ She opened the door and saw a package on the porch.
• Both actions happened in the past — keep both verbs in past tense.

Example 2 — Shift in a Paragraph:

• ❌ The explorers traveled for weeks. They cross rivers and climb mountains.
• ✅ The explorers traveled for weeks. They crossed rivers and climbed mountains.

Example 3 — Acceptable Shift (general truth):

• ✅ Galileo proved that the Earth revolves around the Sun.
• Present tense is correct for the second verb because it states a permanent truth.

ACT Tip: Read the surrounding sentences to determine the established tense. If the passage is in past tense, an underlined verb in present tense is almost certainly the error.

Tense Consistency — Spot the Shift 🔍

Perfect Tenses & Sequence of Events

Present perfect (has/have + past participle) connects a past action to the present:

• ✅ I have lived here for ten years. (started in the past, still true now)

Past perfect (had + past participle) shows that one past action happened before another:

• ✅ By the time the ambulance arrived, the patient had already recovered.
• The recovering happened first, then the ambulance arrived.

Common ACT Pattern — "By the time" / "Before":

• ❌ Before the concert started, the musicians already tuned their instruments.
• ✅ Before the concert started, the musicians had already tuned their instruments.
• The tuning happened before the starting → use past perfect for the earlier event.

ACT Tip: Whenever you see "before," "by the time," or "after" in a sentence with two past events, check whether the earlier event uses past perfect (had + verb).

Choose the Correct Tense ✏️

1. "By the time we arrived, the movie _____ (started / had started)." — Type the correct form.

2. "She _____ (has worked / worked) at the company since 2018." — Type the correct form.

3. "Yesterday, he _____ (walks / walked) to school." — Type the correct form.

Tense ID — Quick Check 🔍

ACT-Style Practice 📋

🔗 Sentence Structure

Part 4 of 7 — Fragments, Run-Ons, Comma Splices & How to Fix Them

The ACT tests your ability to recognize and fix sentence-structure errors. These fall into three categories:

(Some books call both of the last two errors "run-ons." This lesson uses "run-on" for the no-punctuation version and "comma splice" for the comma-only version. The fixes are the same.)

ACT Tip: If an answer choice creates a fragment or a run-on, eliminate it — the ACT never rewards incomplete or improperly joined sentences.

Sentence Fragments

A fragment is a group of words that looks like a sentence but is missing a subject, a verb, or a complete thought.

Common Fragment Types:

1. Dependent clause standing alone:

   • ❌ Because she studied every night.
   • ✅ Because she studied every night, she passed the exam.

2. Phrase without a main verb:

   • ❌ Running through the park on a sunny day.
   • ✅ She was running through the park on a sunny day.

3. "Which" or "That" clause standing alone:

   • ❌ Which was surprising to everyone.
   • ✅ The result, which was surprising to everyone, changed the experiment.

How to Fix a Fragment:

• Attach it to a nearby independent clause, OR
• Add the missing subject or verb to make it complete.

ACT Tip: Words like "because," "although," "since," "when," "which," and "that" create dependent clauses. If you see one standing alone, it's a fragment.

Fragments & Run-Ons — Identify the Error 🔍

Run-Ons & Comma Splices: Four Ways to Fix Them

The four correct ways to join two independent clauses:

1. Period: I studied hard. I passed the test.
2. Semicolon: I studied hard; I passed the test.
3. Comma + coordinating conjunction (FANBOYS): I studied hard, and I passed the test.
4. Subordination: Because I studied hard, I passed the test.

FANBOYS = For, And, Nor, But, Or, Yet, So

Common Mistakes:

• ❌ Comma alone: I studied hard, I passed. (comma splice)
• ❌ No punctuation: I studied hard I passed. (run-on)
• ❌ Comma + non-FANBOYS word: I studied hard, however I passed. (still a splice — "however" is not a FANBOYS conjunction)

Fixing "however," "therefore," "moreover," etc.:

• ✅ I studied hard; however, I still failed.
• ✅ I studied hard. However, I still failed.
• These are conjunctive adverbs, not coordinating conjunctions. When they sit between two independent clauses, they need a semicolon or period before them.
• In the middle of a single clause, a pair of commas is enough: ✅ I studied hard; the test, however, was harder than expected.

Colons and dashes: A colon or a dash can also join two independent clauses, but only when the second clause explains or illustrates the first (I knew I would pass: I had studied every night.). The semicolon is the all-purpose fix for any two closely related clauses.

ACT Tip: If you see two complete sentences joined by only a comma, look for an answer that adds a FANBOYS conjunction, a semicolon, or a period.

Classify the Error ✏️

Type "fragment," "run-on," or "comma splice" for each sentence.

1. "Walking to the store after finishing her homework."

2. "The alarm went off we rushed outside."

3. "The cake looked delicious, nobody wanted to cut it."

Sentence Structure Rules 🔍

ACT-Style Practice 📋

✨ Modifiers & Parallelism

Part 5 of 7 — Dangling Modifiers, Misplaced Modifiers & Parallel Structure

The ACT tests your ability to place modifiers correctly and keep sentence elements parallel. These errors can be subtle, so learning the patterns is essential.

Key Concepts:

Dangling Modifiers

A dangling modifier is an introductory phrase that doesn't logically modify the subject that follows it.

The Rule: The subject right after the comma must be the one doing the action in the introductory phrase.

Example 1 — Dangling:

• ❌ Hoping to win the scholarship, the application was submitted early.
• Who was hoping? Not "the application"!
• ✅ Hoping to win the scholarship, Maria submitted the application early.

Example 2 — Dangling:

• ❌ After reviewing the data, the experiment was redesigned.
• ✅ After reviewing the data, the researchers redesigned the experiment.

Example 3 — Correct:

• ✅ Exhausted from the hike, the campers collapsed into their tents.
• The campers were exhausted — the modifier matches the subject.

ACT Tip: When a sentence starts with an -ing phrase, a past-participle phrase, or an infinitive phrase, check that the subject right after the comma is the one performing that action.

Misplaced Modifiers

A misplaced modifier sits next to the wrong word, so it seems to describe something it shouldn't. Limiting words (only, almost, just, nearly) and descriptive phrases belong right beside what they modify.

• ❌ She almost drove her kids to every game. (She nearly drove but never did?)
• ✅ She drove her kids to almost every game.
• ❌ The waiter served a steak to the customer that was undercooked. (The customer was undercooked?)
• ✅ The waiter served the customer a steak that was undercooked.

Fix: Move the modifier so it touches the word it describes.

Modifier Placement — Spot the Error 🔍

Parallel Structure

Parallelism means that items in a list or comparison must have the same grammatical form.

Example 4 — Faulty Parallelism in a List:

• ❌ The camp offers hiking, swimming, and to canoe.
• ✅ The camp offers hiking, swimming, and canoeing.
• All items should be gerunds (-ing forms).

Example 5 — Parallelism with Correlative Conjunctions:

• Use parallel forms after: both … and, either … or, neither … nor, not only … but also
• ❌ She is not only a talented singer but also dances well.
• ✅ She is not only a talented singer but also a skilled dancer.

Example 6 — Parallelism in Comparisons:

• ❌ Reading a book is more relaxing than to watch TV.
• ✅ Reading a book is more relaxing than watching TV.

ACT Tip: When you see a list or a comparison underlined, check that every element has the same grammatical structure (all nouns, all gerunds, all infinitives, etc.).

Fix the Parallelism ✏️

Rewrite the underlined portion to make it parallel. Type only the corrected word or phrase.

1. "The job requires patience, creativity, and being organized." → Change "being organized" to: _____

2. "He likes to swim, to hike, and running." → Change "running" to: _____

3. "The recipe calls for chopping the onions, dicing the tomatoes, and the peppers should be sliced." → Change the last item to: _____

Modifiers & Parallelism — Quick Check 🔍

ACT-Style Practice 📋

🔤 Commonly Confused Words

Part 6 of 7 — Affect/Effect, Their/There/They're, Its/It's & More

The ACT includes several questions that test whether you know the difference between commonly confused words. These are easy points once you learn the pairs.

Affect vs. Effect & Their/There/They're

Affect vs. Effect:

• Affect is usually a verb: The weather will affect the game.
• Effect is usually a noun: The effect of the storm was devastating.
• Memory trick: Affect = Action (verb); Effect = End result (noun).
• Exception: "effect" can be a verb meaning "to bring about": The new CEO effected major changes.

Their / There / They're:

• Their = possessive: The students opened their books.
• There = location or existence: There are three reasons.
• They're = contraction of "they are": They're going to the movies.

Example 1:

• ❌ The new policy had a negative affect on employee morale.
• ✅ The new policy had a negative effect on employee morale.
• "Effect" is correct because it is a noun (the result).

Example 2:

• ❌ The team celebrated they're victory at the restaurant.
• ✅ The team celebrated their victory at the restaurant.
• "Their" shows possession.

ACT Tip: Substitute "they are" for "they're" — if it doesn't make sense, you need "their" or "there."

Confused Words — Pick the Right One 🔍

Its/It's, Your/You're, Then/Than & Who's/Whose

Its vs. It's:

• Its = possessive (no apostrophe!): The cat licked its paw.
• It's = "it is" or "it has": It's been a long day.
• Test: If you can replace it with "it is," use "it's." Otherwise, use "its."

Your vs. You're:

• Your = possessive: Is this your jacket?
• You're = "you are": You're going to love this.

Then vs. Than:

• Then = time or sequence: We ate dinner, then watched a movie.
• Than = comparison: She is taller than her brother.
• "Then" is not a FANBOYS conjunction, so ", then" cannot join two complete sentences.
  • ❌ We ate dinner, then we watched a movie. (comma splice)
  • ✅ We ate dinner, and then we watched a movie. or We ate dinner; then we watched a movie.

Who's vs. Whose:

• Who's = "who is" or "who has": Who's coming to the party?
• Whose = possessive: Whose book is this?

ACT Tip: Possessive pronouns NEVER use apostrophes: its, your, whose, their. Apostrophes in these words always mean contractions.

Choose the Correct Word ✏️

1. "The dog wagged _____ (its/it's) tail happily." — Type the correct word.

2. "She is smarter _____ (then/than) her older brother." — Type the correct word.

3. "_____ (Whose/Who's) responsible for this mess?" — Type the correct word.

Commonly Confused Words — Quick Check 🔍

ACT-Style Practice 📋

🏆 Review & Mixed Practice

Part 7 of 7 — Error-Identification Cheat Sheet & Mixed ACT English Questions

This final lesson brings together everything from Parts 1–6. Use the cheat sheet below for quick reference, then tackle the mixed practice questions.

Grammar Error Cheat Sheet

ACT English — Test-Day Strategy

Time Management (Enhanced ACT):

• You have 35 minutes for 50 questions, about 42 seconds per question.
• Every question has 4 answer choices, and there is no penalty for guessing, so never leave a question blank.
• If a question is taking much longer than a minute, make your best guess, mark it, and move on.
• English counts toward your composite score, along with Math and Reading (Science is optional and reported separately).

The ACT English Process:

1. Read the sentence with the underlined portion.
2. Identify the error category (agreement? tense? structure? word choice?).
3. Eliminate wrong answers — if an answer creates a new error, cross it out.
4. Choose the most concise correct option — the ACT rewards clarity and brevity.

"NO CHANGE" Tips:

• "NO CHANGE" is a real answer, not a trap. It is correct often enough that you shouldn't avoid it.
• But always check the other three options before settling on NO CHANGE.

Common Traps:

• Answers that sound fancy but introduce grammatical errors.
• Answers that fix one problem but create another (e.g., fixing a comma splice but creating a fragment).
• Wordiness — the ACT prefers the shortest answer that is grammatically correct and clear.

Mixed Review — Grammar Concepts 🔍

Quick Error-Identification Practice

Read each sentence and identify the error type before looking at the answer:

Sentence A: "The effects of climate change is felt worldwide." → Subject-verb agreement — "effects" is plural, so the verb should be "are."

Sentence B: "The teacher told the students that they should bring his or her own calculator." → Pronoun agreement — "students" is plural, so use "their" instead of "his or her."

Sentence C: "She went to the store, she bought groceries." → Comma splice — Two independent clauses joined by only a comma. Fix: add "and" or use a semicolon.

Sentence D: "Tired and hungry, the pizza was devoured by the hikers." → Dangling modifier — "Tired and hungry" describes the hikers, not the pizza. Fix: "Tired and hungry, the hikers devoured the pizza."

Sentence E: "He prefers reading books more then watching television." → Commonly confused words — "then" should be "than" (comparison).

Name That Error ✏️

Identify the error type in each sentence. Type your answer.

1. "Neither the students nor the teacher were happy with the results." → Error type:

2. "The report, which was written by the interns, have several typos." → Error type:

3. "Running late for the interview, the car wouldn't start." → Error type:

Final Review — Rule Recall 🔍

ACT-Style Mixed Practice 📋