ACT grammar questions become easier to review when you can name the job a word or punctuation mark is doing. Start with sentence boundaries, then agreement and pronouns, modifiers, punctuation, and parallel structure. Those topics give you a practical way to explain an answer instead of choosing whatever sounds familiar.
Grammar is one part of English. ACT also tests how a passage develops and organizes ideas, so a correct sentence can still be the wrong editorial choice. The current English section has 50 delivered questions in 35 minutes. ACT's section guide describes both conventions and rhetorical skills.
The examples below are original teaching examples, not questions reproduced from an official test.
Start by finding the sentence's backbone
Before choosing punctuation, identify the subject, the verb, and whether the thought is complete.
“The museum's collection of maps includes several recent donations” has the subject collection, not maps or donations. Temporarily setting aside “of maps” helps you see why the singular verb fits. Do not permanently ignore descriptive phrases: restore them before checking whether the complete sentence makes sense.
A clause with a subject and verb can still depend on another clause. “Although the museum opened early” leaves you waiting for the main point. A complete version is “Although the museum opened early, the first visitors arrived at noon.”
Make these two checks before trusting your ear:
- What noun or pronoun performs the main action?
- Can this clause stand as a complete sentence in this context?
Repair sentence boundaries
Two independent clauses cannot normally be joined by a comma alone.
Consider: “The robotics club finished its prototype, the battery still needed charging.” Both sides could stand alone. Three possible repairs are:
- “The robotics club finished its prototype. The battery still needed charging.”
- “The robotics club finished its prototype; the battery still needed charging.”
- “The robotics club finished its prototype, but the battery still needed charging.”
The last version also identifies a contrast. On a multiple-choice question, use the options and the surrounding passage to decide which repair meets the sentence's purpose.
An original practice question
Choose the grammatically correct completion:
“The greenhouse roof was repaired ___ the seedlings remained indoors until Friday.”
A. , however,
B. ; however,
C. however;
D. , however;
Answer: B. The text on each side of the semicolon is an independent clause. “However” introduces the second clause and is followed by a comma. Choice A creates a comma splice. Neither C nor D supplies the required boundary in the correct place.
Do not turn this into “however always needs a semicolon.” Its punctuation depends on its position and the clauses around it.
Match verbs and pronouns to the right words
Intervening phrases are common sources of confusion. In “One of the notebooks contains the original sketch,” one controls the verb. A nearby plural noun does not change that relationship.
Pronouns also need clear antecedents. “Maya handed Leila her notes because she had missed the lecture” leaves two possible people for “she.” If the intended meaning is that Leila missed the lecture, naming Leila removes the ambiguity.
| Check | Unclear or incorrect version | More precise version |
|---|---|---|
| Subject–verb agreement | The list of assignments are online. | The list of assignments is online. |
| Pronoun number | The two instruments were packed in its cases. | The two instruments were packed in their cases. |
| Pronoun reference | Ben told Amir that his project was ready. | Ben told Amir that Ben's project was ready. |
| Verb sequence | Last spring, the team builds the model and tested it. | Last spring, the team built the model and tested it. |
The repeated name in the third example is deliberately explicit. In a real passage, a smoother rewrite may be available. Your goal is clear meaning, not mechanical repetition.
Attach modifiers to what they describe
An introductory description should connect logically to the subject that follows.
“Walking through the exhibition, the paintings caught Nora's attention” suggests that the paintings were walking. A repair is “Walking through the exhibition, Nora noticed the paintings.”
For a placement problem, ask who or what can actually perform the action in the introductory phrase. Then read the whole sentence to verify the intended meaning.
A modifier can also be misplaced without being at the beginning. Compare “The coach almost reviewed every exercise” with “The coach reviewed almost every exercise.” The first emphasizes nearly doing the reviewing; the second says most exercises were reviewed. Small placement changes can alter the claim.
Use commas for a specific reason
A comma is not a general instruction to pause. Look for a grammatical function.
Use paired commas around a removable interruption: “The new bridge, designed by a local engineer, opened in May.” Remove the interruption and the sentence still reads “The new bridge opened in May.”
Do not place a comma between a subject and its verb just because the subject is long: “The engineer who supervised the final inspection approved the bridge.” No comma belongs between “inspection” and “approved.”
Restrictive information identifies which person or object is meant; nonrestrictive information adds an aside. “Students who finished the survey received a voucher” selects a group. Commas around that relative clause would change the implication. Let the passage's meaning guide the punctuation.
Distinguish possession from a contraction
These pairs test different jobs:
- its shows possession; it's means “it is” or “it has.”
- their shows possession; they're means “they are.”
- whose shows possession; who's means “who is” or “who has.”
Expand the contraction before selecting it. “The observatory updated its schedule” needs possession. Substituting “it is” would not work.
For noun possession, establish both number and ownership. “The student's experiment” belongs to one student. “The students' experiment” belongs to multiple students. The context, not the presence of a final s alone, determines the answer.
Keep coordinated ideas parallel
Items connected in a list should have compatible grammatical forms.
“The workshop teaches students to measure samples, record observations, and analyzing results” mixes infinitives with an -ing form. Change the final item to “analyze results.”
Parallelism can cross a longer sentence. In a comparison, verify that the compared things are equivalent: “The town's bus service is more frequent than the neighboring town” compares a service with a town. “More frequent than the neighboring town's bus service” fixes the relationship.
Build a rule-based review habit
After a short practice set, record the rule, the evidence, and a new sentence of your own. A useful entry is “Comma splice: both sides were complete clauses; a semicolon or conjunction was needed.” “Bad punctuation” does not tell you what to practice tomorrow.
Also review correct guesses. If you selected the right option because it sounded polished, revisit the clause structure before crediting that skill as secure. ACT's English standards can help name the underlying convention.
For a timed practice form, use its matching scoring key and the ACT score calculator. A section score summarizes a performance; your rule notes identify the work that can improve the next attempt.
Questions students ask
Should I always choose the shortest answer?
No. Brevity helps only when the answer preserves required meaning and correct grammar. A short fragment or an answer that deletes essential context is still wrong.
Should I memorize every punctuation exception first?
Start with the patterns your actual errors reveal. Being able to identify a clause and explain a sentence boundary is more useful than memorizing a long list you cannot apply.
How do I know I have learned a rule?
Try a new example after a delay, explain the answer without looking at notes, and identify why a plausible alternative fails. Repeating a remembered answer is weaker evidence than transferring the rule to a different sentence.
Keep Reading
- ACT English Strategy: Read Like an Editor and Keep Moving
- ACT English Organization Questions: Placement, Purpose, and Paragraph Flow
- ACT Prep Below 20: Rebuild the Skills Behind Your Score
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