PSAT 10 Standard English Conventions: Grammar, Usage, and Punctuation for the Reading & Writing Section

Boundaries

Boundaries are the rules that mark where one sentence or clause ends and another begins. On the PSAT 10, boundary questions test whether you can:

Separate independent clauses correctly (complete thoughts that could stand alone as sentences)
Attach dependent clauses correctly (incomplete thoughts that rely on an independent clause)
Use punctuation to show relationships between ideas without creating run-ons, comma splices, or fragments

Getting boundaries right matters because punctuation is not just “correctness”—it’s meaning. A boundary choice signals whether ideas are equal, closely linked, explanatory, or interruptive. The PSAT often gives you answer choices that are all “close” in meaning, so the only way to choose confidently is to know what each boundary mark can and cannot do.

Core building blocks: independent vs. dependent clauses

A clause is a group of words with a subject and a verb.

An independent clause expresses a complete idea.
- Example: The exhibit opens tomorrow.
A dependent clause (also called a subordinate clause) begins with a subordinating word (like because, although, when, if, since) and cannot stand alone.
- Example: Because the exhibit opens tomorrow (you’re left waiting for what happened because of that).

A reliable way to handle boundary questions is to label each side of the punctuation:

Find the verb on each side.
Ask: does each side contain a subject + verb and express a complete thought?
Decide what punctuation can legally connect what you have.

Sentence boundary errors you must recognize

Boundary questions often hide one of these three problems:

Run-on sentence: two independent clauses joined with no punctuation or connector.
- The exhibit opens tomorrow it will be crowded.
Comma splice: two independent clauses joined by a comma alone.
- The exhibit opens tomorrow, it will be crowded.
Fragment: a dependent clause or incomplete idea punctuated as a sentence.
- Because the exhibit opens tomorrow.

The test frequently offers tempting “comma” answers because commas feel natural in speech. In formal writing, though, punctuation must match clause structure.

The period and the semicolon: separating equal sentences

A period ends a sentence. Use it between two independent clauses when you want a full stop.

A semicolon is a “soft period.” It can join two closely related independent clauses without a conjunction.

Correct: The exhibit opens tomorrow; it will be crowded.
Incorrect: Because the exhibit opens tomorrow; it will be crowded. (left side isn’t independent)

A semicolon is especially useful when the clauses are tightly connected in meaning—think of it as saying, “these could be two sentences, but they belong together.”

The comma: four high-frequency jobs

Commas show small boundaries inside sentences. On the PSAT, comma questions are often really clause questions.

1) Comma + coordinating conjunction (FANBOYS)

Use a comma before for, and, nor, but, or, yet, so when they join two independent clauses.

The exhibit opens tomorrow, so the museum extended its hours.

If the second part is not an independent clause, you typically do not use a comma.

The museum extended its hours because the exhibit opens tomorrow. (no comma)

2) Introductory dependent clause or phrase

When a sentence begins with a dependent clause or a long introductory phrase, use a comma after it.

Because the exhibit opens tomorrow, the museum extended its hours.
After months of planning, the team finally launched the project.

This matters because readers need a clear sign of where the “setup” ends and the main clause begins.

3) Nonessential (parenthetical) information

Use commas to set off information that could be removed without changing the core identity of the noun.

The curator, who studied textile history, designed the display.

If the information is essential (it identifies which one you mean), do not use commas.

Curators who study textile history often design such displays. (not all curators)

A common PSAT trap is mixing these up—adding commas around essential information weakens meaning and can become ungrammatical.

4) Items in a list

Use commas to separate items in a series.

The exhibit includes maps, photographs, and recorded interviews.

The colon: introducing what comes next

A colon signals that what follows will explain, define, illustrate, or list something mentioned before. The key boundary rule:

The text before a colon must be an independent clause.

Correct:

The exhibit has one goal: to show how cities evolve.

Incorrect:

The exhibit’s goal is: to show how cities evolve. (the part before the colon is not a complete clause in standard usage)

Colons are especially common when the second part is a list, an example, or a restatement.

The dash: emphasis or interruption

An em dash (—) can function like a stronger comma or like parentheses. It often marks an interruption, an explanation, or a dramatic emphasis.

The museum’s newest acquisition—an original field notebook—will be displayed next week.

Boundary-wise, dashes must be used consistently:

If you open with a dash, you typically close with another dash (unless the dash ends the sentence).
Don’t mix a dash on one side with a comma on the other in standard formal punctuation.

A frequent mistake is using dashes where a colon is needed (or vice versa). A dash is stylistic emphasis; a colon is a logical “here comes the explanation/list.”

Parentheses: quiet, removable information

Parentheses set off extra information that is least important to the sentence’s main flow.

The survey included 200 participants (all volunteers from local colleges).

If the parenthetical is removed, the sentence should still be grammatically complete.

Combining punctuation with transitions

PSAT passages often include transitions like however, therefore, for example, in addition. These words do not magically fix run-ons.

Two common correct patterns:

Semicolon + transition + comma
- The data were incomplete; however, the trend was clear.
Period + transition + comma
- The data were incomplete. However, the trend was clear.

A common wrong pattern:

The data were incomplete, however the trend was clear. (usually a comma splice)

Worked examples (how to reason, not just what to pick)

Example 1: Run-on vs. correct boundary

Sentence: The team revised the proposal it still needed approval.

Left side: The team revised the proposal (independent)
Right side: it still needed approval (independent)

Valid fixes include:

The team revised the proposal; it still needed approval.
The team revised the proposal, but it still needed approval.
The team revised the proposal. It still needed approval.

Invalid fix:

The team revised the proposal, it still needed approval. (comma splice)

Example 2: Colon rule

Sentence: Three tools helped the researchers: microscopes, sensors, and cameras.

Before colon: Three tools helped the researchers (independent clause) → colon is allowed.

But:

The tools were: microscopes, sensors, and cameras. is usually not considered standard because The tools were sets up a predicate complement; the colon is not needed and often tested as incorrect on College Board-style conventions questions.

Exam Focus

Typical question patterns:
- Choosing the correct punctuation between two clauses (period vs. semicolon vs. comma + conjunction vs. colon).
- Fixing a run-on, comma splice, or fragment by adjusting punctuation and/or adding a conjunction.
- Deciding whether commas should set off a phrase/clause (nonessential) or not (essential).
Common mistakes:
- Using a comma to join two independent clauses without a conjunction (comma splice). Treat commas as “small” boundaries, not sentence-enders.
- Placing a colon after an incomplete lead-in (the part before a colon must stand alone as a sentence).
- Believing transitions like however function as conjunctions. They don’t—you still need a period or semicolon.

Form, Structure, and Sense

Form, Structure, and Sense questions test whether the forms of words (especially verbs and pronouns), the structure of a sentence, and the intended meaning all fit together. In other words, even if a sentence has the “right” punctuation, it can still be wrong if the grammar creates a mismatch—like a singular subject with a plural verb, an unclear pronoun, or a modifier that attaches to the wrong word.

This category is less about memorizing rules in isolation and more about checking the sentence as a system:

Who is doing what (subject–verb relationship)?
When is it happening (tense and sequence)?
To whom/what does each pronoun refer (clarity and agreement)?
Do comparisons and lists match in grammatical shape (parallelism and logical comparison)?

Verbs: tense, agreement, and consistency

Verbs carry two big kinds of information: time (tense) and match (agreement with the subject).

Subject–verb agreement

Subject–verb agreement means the verb form matches the subject in number.

Singular subject → singular verb: The collection includes rare coins.
Plural subject → plural verb: The coins include rare designs.

What makes this tricky on the PSAT is that the subject and verb are often separated by extra phrases.

The collection of rare coins includes a silver denarius.

Even though coins is plural, the subject is collection (singular). Prepositional phrases like of rare coins do not change the subject’s number.

Common trap: intervening phrases

The results, along with a brief summary, are posted online.
- Subject is results (plural) → are is correct.
The summary, along with the results, is posted online.
- Subject is summary (singular) → is is correct.

Verb tense and sequence of tenses

Verb tense should reflect when actions happen and should stay consistent unless the time actually changes.

Consistent present: Researchers argue that the method reduces errors.
Past narrative: The team tested the device and recorded the results.

A useful way to avoid errors is to identify the passage’s “time frame.” If the passage describes a completed study, past tense is often the default; if it describes a general fact, present tense is often the default.

Common trap: unnecessary tense shift

Awkward/incorrect: The team tested the device and records the results.
Improved: The team tested the device and recorded the results.

Verb form: finite vs. nonfinite (and why it matters)

Sometimes the issue is not tense but verb form—whether the verb can serve as the main verb of a clause.

A finite verb is a fully functioning main verb: runs, ran, is running, has run.
A nonfinite verb (like an infinitive or participle) cannot be the only verb of an independent clause: to run, running, run (as a participle).

Fragment risk:

Running through the park. (no finite verb—this is not a complete sentence)

Pronouns: clarity, agreement, and case

Pronouns are placeholders, but they must point clearly to a specific noun (antecedent) and match it.

Pronoun–antecedent agreement

A pronoun must match its antecedent in number (and, when relevant, person).

Each student submitted his or her draft. (traditional formal agreement)
Students submitted their drafts. (plural subject makes their correct)

College Board-style questions often reward the cleanest fix: if each or every creates awkward singular pronoun choices, rewriting to plural can solve agreement smoothly.

Pronoun clarity (avoiding ambiguous “this/that/it/they”)

A pronoun must have a clear referent.

Ambiguous:

The committee discussed the proposal and the budget, but it was rejected.

What was rejected—the proposal or the budget? A clearer version names the noun:

…but the proposal was rejected.

A very common PSAT pattern is fixing “this” or “that” by adding a noun:

Vague: This improved over time.
Clear: This process improved over time.

Pronoun case (I/me, who/whom)

Pronoun case depends on the pronoun’s job in the sentence.

Subject case: I, he, she, we, they, who
Object case: me, him, her, us, them, whom

A quick method: remove extra words and test.

Between you and (I/me)… → It’s after a preposition (between), so it needs an object: me.

For who/whom:

Use who when it functions as a subject.
Use whom when it functions as an object.

Test by substituting:

who ↔ he/she/they
whom ↔ him/her/them

Example:

The author who won the award spoke. (who = he)
The author whom the judges praised spoke. (whom = them; judges praised whom)

Modifiers: placing descriptions next to what they describe

A modifier is a word or phrase that describes something else. Modifier questions test whether the description is placed so it clearly attaches to the right word.

Misplaced and dangling modifiers

A modifier is misplaced when it is too far from the word it describes.

Misplaced: She served sandwiches to the children on paper plates. (Were the children on plates?)
Clear: She served the children sandwiches on paper plates.

A modifier dangles when the sentence doesn’t supply the person/thing that the modifier describes.

Dangling: Walking to the station, the rain soaked my jacket. (Rain wasn’t walking.)
Fixed: Walking to the station, I got soaked by the rain.

On the PSAT, dangling modifier questions often appear at the start of a sentence (introductory -ing phrases). The fix usually requires making the subject of the main clause the “doer” of the introductory action.

Parallel structure: matching grammar to show equal ideas

Parallelism means items in a list or paired structure have the same grammatical form. Parallel structure matters because it helps readers process equality—if ideas are equal, their grammar should look equal.

Common parallel structures:

Lists: The job requires planning, testing, and reporting.
Paired words: both…and, either…or, not only…but also

Nonparallel:

The job requires planning, to test, and reporting.

The fix is to choose one form and stick to it (all -ing, all infinitives, all nouns, etc.).

Comparisons and logical structure (sense)

Some questions are about whether the sentence makes sense logically, even if it’s grammatically “possible.” Two high-frequency sense issues are comparisons and reference.

Logical comparisons

When comparing, make sure you are comparing like with like.

Illogical:

The speed of the new printer is faster than the old model.

You can’t compare speed to model. Fix by comparing speed to speed (or printer to printer):

The new printer is faster than the old model.
The speed of the new printer is faster than the speed of the old model.

Clear reference (especially with “which” and “that”)

Relative clauses beginning with which or that should clearly modify the noun right before them.

Unclear:

She reviewed the article about coral reefs, which was fascinating. (Was the article fascinating, or the reefs?)

Clearer:

She reviewed the article, which was fascinating, about coral reefs. (article)
She reviewed an article about coral reefs, which are fascinating. (reefs)

Sentence structure choices that affect meaning

Form/structure questions sometimes ask you to choose between grammatically correct options based on what best matches the intended meaning.

Active vs. passive voice (clarity and emphasis)

Active voice: subject performs the action (The scientist analyzed the samples.)
Passive voice: subject receives the action (The samples were analyzed by the scientist.)

Passive voice is not always “wrong,” but it can hide the actor. If the passage cares about who did something, active voice is usually clearer.

Concision and redundancy (when it impacts correctness)

While “concision” is often associated with other domains, Standard English Conventions questions can still involve eliminating redundant structures that create awkward or ungrammatical phrasing.

Redundant:

Because of the fact that → usually because
In order to → often just to

On the PSAT, the best answer is typically the simplest one that preserves the exact meaning and remains grammatically correct.

Worked examples (diagnosing the underlying rule)

Example 1: Agreement with intervening phrases

Sentence: The list of required materials are posted online.

Subject is list (singular), not materials.
Correct verb: is

Corrected: The list of required materials is posted online.

Example 2: Dangling modifier

Sentence: To improve accuracy, the experiment was repeated three times.

Who wanted to improve accuracy? The sentence’s subject (the experiment) can’t have that intention.

Fix by naming the actor:

To improve accuracy, the researchers repeated the experiment three times.

Example 3: Parallelism

Sentence: The program aims to educate communities, reducing waste, and to promote recycling.

The list mixes forms. Choose a consistent pattern, such as infinitives:

The program aims to educate communities, to reduce waste, and to promote recycling.

Or -ing forms:

The program aims at educating communities, reducing waste, and promoting recycling.

Example 4: Pronoun ambiguity

Sentence: When the engineers tested the prototype next to the original, it failed.

“It” could refer to either item. Fix by naming the noun:

…the prototype failed.

Exam Focus

Typical question patterns:
- Selecting the verb form that matches the subject and the passage’s time frame.
- Fixing pronoun problems (agreement, case, or unclear reference).
- Choosing a revision that eliminates a dangling/misplaced modifier or restores parallel structure.
Common mistakes:
- Letting a nearby plural noun “trick” you into a plural verb when the true subject is singular (watch for of, along with, in addition to phrases).
- Using pronouns like this/it/they without a clear antecedent—if you can’t point to a specific noun, the pronoun is risky.
- Mixing grammatical forms in lists (e.g., nouns + -ing verbs + infinitives). If ideas are equal, their grammar should match.