10 Grammar Rules Tested on Every SHSAT
The SHSAT Revising/Editing section accounts for 11 of your 57 ELA questions. That might seem small compared to Reading Comprehension's 46 questions, but here is the thing: R/E questions are the most improvable section on the entire test. The grammar rules are finite, learnable, and predictable.
Our question bank contains 448 Revising/Editing questions across six subtopics. After analyzing every one of them, we identified the 10 grammar rules that appear on virtually every SHSAT. Learn these rules cold, and you turn R/E into easy points.
One pattern stands out from our common mistakes data: the number one error students make is choosing a "correction" that sounds okay but does not actually fix the grammar rule being tested. Keep that in mind as you read each rule below.
1. Subject-Verb Agreement
What it is: The subject and verb in a sentence must match in number. Singular subjects take singular verbs. Plural subjects take plural verbs.
The error:
The collection of rare stamps were donated to the museum last spring.
The correction:
The collection of rare stamps was donated to the museum last spring.
Why students get it wrong: The noun closest to the verb ("stamps") is plural, so "were" sounds right. But the actual subject is "collection," which is singular. The SHSAT loves inserting prepositional phrases between the subject and verb to create this exact confusion.
Test day tip: Cross out everything between the subject and verb. Read the sentence without the interrupting phrase: "The collection... was donated." Now it is obvious.
This pattern falls under our grammar_usage subtopic, the most heavily tested R/E category with 81 questions in our bank.
2. Pronoun-Antecedent Agreement
What it is: A pronoun must agree in number with the noun it replaces (its antecedent). A singular noun needs a singular pronoun. A plural noun needs a plural pronoun.
The error:
Each student must bring their calculator to the exam.
The correction:
Each student must bring his or her calculator to the exam.
Or, better for the SHSAT:
All students must bring their calculators to the exam.
Why students get it wrong: "Their" following a singular noun has become common in everyday speech. On the SHSAT, grammatical precision wins. Words like "each," "every," "anyone," and "nobody" are singular, even though they refer to groups of people.
Test day tip: Circle every pronoun. Draw an arrow to the noun it refers to. Do they match in number? If not, you have found the error.
3. Verb Tense Consistency
What it is: Within a sentence or passage, verb tenses should remain consistent unless there is a logical reason for a shift (like moving from past to present).
The error:
The scientist examined the samples carefully and records her findings in the lab notebook.
The correction:
The scientist examined the samples carefully and recorded her findings in the lab notebook.
Why students get it wrong: Students focus on whether each verb "sounds right" individually rather than checking whether they match each other. On R/E passages, tense shifts are often subtle, spanning multiple sentences.
Test day tip: Underline every verb in the paragraph. Check that they all live in the same time period. If one suddenly switches tense without a clear reason (a time signal like "now" or "previously"), that is your error.
4. Comma Splices and Run-On Sentences
What it is: Two independent clauses (complete sentences) cannot be joined by just a comma. That is a comma splice. Two independent clauses with no punctuation at all create a run-on sentence.
The error (comma splice):
The library closes at 9 PM, students must leave by then.
The error (run-on):
The library closes at 9 PM students must leave by then.
The corrections:
The library closes at 9 PM; students must leave by then.
The library closes at 9 PM, so students must leave by then.
The library closes at 9 PM. Students must leave by then.
Why students get it wrong: The comma splice "looks fine" because there is a pause where the comma sits. Students do not realize a comma alone cannot connect two complete thoughts. Our punctuation subtopic has 73 questions, and comma splices are the single most common error type.
Test day tip: Cover everything after the comma. Is the first part a complete sentence? Now cover everything before the comma. Is the second part also a complete sentence? If both pass, you need more than a comma between them.
5. Apostrophe Usage: Possessives vs. Contractions
What it is: Apostrophes show possession (the dog's bone) or mark contractions (it's = it is). Mixing these up, especially with its/it's, your/you're, and their/they're, is a classic SHSAT trap.
The error:
The school posted it's new dress code policy on the website.
The correction:
The school posted its new dress code policy on the website.
Why students get it wrong: "It's" looks possessive because we associate apostrophes with possession. But "it's" always means "it is" or "it has." The possessive form of "it" is "its" with no apostrophe. This exception trips up even strong writers.
Test day tip: Every time you see an apostrophe, expand it. Does "it's" make sense as "it is"? If not, it should be "its." Apply the same test to your/you're and their/they're.
6. Semicolons and Colons
What it is: A semicolon connects two related independent clauses. A colon introduces a list, explanation, or elaboration after an independent clause.
The error:
The museum featured three exhibits, ancient Egypt, medieval Europe, and modern art.
The correction:
The museum featured three exhibits: ancient Egypt, medieval Europe, and modern art.
Why students get it wrong: Students often treat semicolons and colons as interchangeable, or avoid them entirely. On the SHSAT, you need to know that a semicolon requires a complete sentence on both sides, while a colon requires a complete sentence only before it.
Test day tip: For semicolons, apply the "period test." Could you replace the semicolon with a period and have two complete sentences? If yes, the semicolon works. For colons, check that the words before the colon form a complete sentence on their own.
7. Parallel Structure
What it is: Items in a list or comparison must follow the same grammatical pattern. If one item is a noun, all items should be nouns. If one item starts with a verb, all items should start with verbs.
The error:
The coach expects players to arrive on time, practicing with intensity, and that they show respect to officials.
The correction:
The coach expects players to arrive on time, practice with intensity, and show respect to officials.
Why students get it wrong: Each item in the broken version makes sense on its own. Students read for meaning rather than structure. Our sentence_structure subtopic has 76 questions, and parallel structure errors account for a significant portion of them.
Test day tip: Find the list. Strip each item down to its core structure. Write them vertically:
- to arrive on time
- practicing with intensity ← does not match
- that they show respect ← does not match
The mismatch becomes obvious when you stack them.
8. Misplaced and Dangling Modifiers
What it is: A modifier (a descriptive word or phrase) must sit next to the thing it describes. When it does not, the sentence says something unintended or absurd.
The error:
Running through the park, the squirrel startled Maria.
The correction:
Running through the park, Maria was startled by a squirrel.
Or: While Maria was running through the park, a squirrel startled her.
Why students get it wrong: The original sentence "makes sense" if you think about it for a second. But grammatically, it says the squirrel was running through the park. The SHSAT tests whether you catch the literal meaning, not the intended meaning. This is one of the hardest sentence_structure patterns, with 27 of 76 questions rated hard difficulty.
Test day tip: When a sentence starts with a descriptive phrase followed by a comma, the very next noun should be the person or thing being described. If it is not, the modifier is misplaced.
9. Transition Words and Logical Flow
What it is: Transition words (however, therefore, furthermore, in contrast) must match the logical relationship between ideas. Using "however" when you mean "furthermore" changes the meaning entirely.
The error:
The experiment produced unexpected results. Furthermore, the researchers decided to redesign the study.
The correction:
The experiment produced unexpected results. Therefore, the researchers decided to redesign the study.
Why students get it wrong: Both transitions sound "formal" and "academic," so students pick the one that feels right. But "furthermore" means "in addition" (adding a similar idea), while "therefore" means "as a result" (showing cause and effect). Our organization_transitions subtopic has 74 questions dedicated to exactly this skill.
Test day tip: Ignore the transition word. Read the two sentences. What is the relationship? Same direction (also, furthermore, moreover)? Opposite direction (however, nevertheless, on the other hand)? Cause and effect (therefore, consequently, as a result)? Pick the transition that matches.
For a deeper look at how these questions appear in the digital format, check out our guide to SHSAT digital question types.
10. Conciseness and Redundancy
What it is: Good writing is concise. The SHSAT tests whether you can identify unnecessary words, redundant phrases, and wordy constructions.
The error:
The reason the project failed is because of the fact that the team lacked sufficient funding.
The correction:
The project failed because the team lacked funding.
Why students get it wrong: Longer answers feel "more correct" or "more complete." Students pick the wordiest option because it seems thorough. In reality, the SHSAT rewards the clearest, most direct phrasing. Our precise_language_style subtopic has 73 questions, with 25 rated hard, making it one of the trickiest R/E categories.
Test day tip: When two answer choices say the same thing but one uses fewer words, the shorter one is almost always correct. Watch for these red flags: "the reason is because," "in order to" (just use "to"), "due to the fact that" (just use "because"), "at this point in time" (just use "now").
How These 10 Rules Break Down by Subtopic
| Subtopic | Questions | Rules Covered | Difficulty |
|---|---|---|---|
| Grammar/Usage | 81 | #1, #2, #3 | 33 easy, 38 medium, 10 hard |
| Punctuation | 73 | #4, #5, #6 | 32 easy, 36 medium, 5 hard |
| Sentence Structure | 76 | #7, #8 | 10 easy, 39 medium, 27 hard |
| Organization/Transitions | 74 | #9 | 32 easy, 37 medium, 5 hard |
| Precise Language/Style | 73 | #10 | 12 easy, 36 medium, 25 hard |
| Topic Development | 70 | General editing | 10 easy, 35 medium, 25 hard |
Notice the pattern: grammar_usage and punctuation lean easier, while sentence_structure and precise_language_style lean harder. Start your practice with rules 1-6, then tackle rules 7-10 as your confidence builds.
The Common Mistakes Pattern You Need to Know
After analyzing the common_mistakes data across all 448 R/E questions, one trend dominates everything else: students pick answers that "fix something" but do not fix the right thing.
Here is what that looks like in practice. A question presents a sentence with a subject-verb agreement error. The answer choices include:
- (A) No change
- (B) A version that fixes a comma but leaves the subject-verb error
- (C) A version that fixes the actual subject-verb error
- (D) A version that changes the vocabulary but leaves the error
Students gravitate toward (B) because they see a change was made and it "looks better." But the core error remains. The SHSAT is not asking you to make the sentence prettier. It is asking you to fix the specific grammatical problem.
This is why knowing the 10 rules matters more than having a general "ear" for English. When you can name the rule being tested, you can verify whether the answer choice actually addresses it.
Your R/E Study Strategy
Week 1-2: Learn all 10 rules. Study the examples above until you can name each error type on sight.
Week 3-4: Practice with targeted R/E questions on SHS Prep. Start with grammar_usage (easiest, most tested) and punctuation.
Week 5-6: Move to sentence_structure and precise_language_style (harder categories). Focus on parallel structure and modifier errors.
Week 7-8: Take full mock exams and track which rules you still miss. Our mock exams include 90 R/E questions across all six subtopics, including drag-to-blank and single-drag question types that match the real digital format.
Ongoing: Before answering any R/E question, ask yourself: "Which of the 10 rules is being tested here?" If you can name it, you are 80% of the way to the right answer.
For a comprehensive look at all ELA sections, including Reading Comprehension strategies, see our ELA reading guide. And if you are building a full study plan, our week-by-week study schedule maps out exactly when to focus on grammar within your broader prep timeline.
Starting Fall 2026, the SHSAT becomes computer-adaptive. The grammar rules themselves will not change, but the way questions are delivered will. Practicing on a digital platform now builds the interface familiarity you will need on test day.
