KeplarSAT Grammar Rules: Every Punctuation and Grammar Rule the Digital SAT Tests
The punctuation and grammar rules behind the digital SAT's Standard English Conventions questions: boundaries, semicolons, colons, agreement, verb tense, modifiers and possessives.
SAT grammar questions (Standard English Conventions) are 11 to 15 of the 50 scored Reading and Writing questions, and they test a short list of rules. Most come down to one check: is each side of the blank a complete sentence? Learn the boundary rules and agreement rules below and these become some of the most reliable points on the test.
The one check that settles most questions
An independent clause can stand alone as a sentence: it has a subject and a verb and expresses a complete thought ("The museum reopened"). A dependent clause or phrase can't ("When the museum reopened", "after years of repairs"). Before looking at the choices, mark whether the words before and after the blank are independent.
Boundaries: joining and separating sentences
| Between… | Correct options | Never |
|---|---|---|
| Two independent clauses | Period · semicolon · comma + FANBOYS (for, and, nor, but, or, yet, so) · colon if the second explains the first | A comma alone (comma splice) · nothing (run-on) |
| Independent + dependent | Comma (or nothing, depending on order) | Semicolon · period |
| Independent + list or explanation | Colon · single dash | Colon after an incomplete clause ("The colors are: red…") |
Example. "The reef had recovered faster than expected ___ researchers credited the cooler summer." Both sides are independent, so a semicolon, a period, or ", and" works. A comma alone does not.
Semicolons
A semicolon works like a period: both sides must be complete sentences. The only exception is separating items in a list when the items already contain commas.
Colons and dashes
A colon must follow a complete sentence and introduces what comes next: a list, an explanation or an example. A single dash can do the same job. A pair of dashes works like a pair of commas around extra information.
Commas around extra information
Information that could be removed without breaking the sentence gets a matching pair of commas, dashes or parentheses, never a mix. "The author, who grew up in Lagos, wrote the novel in a year." The second comma is required.
Don't put a comma between a subject and its verb, or between a verb and its object. "The scientists who ran the study found…" needs no comma.
Form, Structure, and Sense
Subject–verb agreement
Find the real subject and ignore what sits between it and the verb. "The list of approved books is posted online." Prepositional phrases ("of approved books") never contain the subject.
Pronoun agreement
A pronoun must match the noun it refers to in number. "Each of the teams submitted its report." Watch for collective nouns (team, committee, company), which take singular pronouns.
Verb tense and form
Match the tense of the surrounding sentences unless the passage signals a change in time. If the paragraph is in the past tense, the blank almost always is too.
Modifiers
An introductory phrase describes whatever comes right after the comma. "Built in 1890, the bridge was…" is correct; "Built in 1890, engineers restored…" says the engineers were built in 1890.
Possessives and plurals
- Singular possessive: the scientist's notes. Plural possessive: the scientists' notes.
- Its is possessive; it's means "it is". Likewise their vs they're, whose vs who's.
- A plain plural never takes an apostrophe: "the 1990s", "several photos".
How to practise grammar efficiently
- Do 15–20 Standard English Conventions questions from the College Board question bank.
- For every miss, write the rule in one line in your error log ("comma splice: comma alone can't join two sentences").
- Redo the misses two days later, then a week later. Grammar rules stick fast once you've written them down yourself.
Then move on to transitions, which are the other quick win in Reading and Writing.
Common questions
How many grammar questions are on the SAT?
Standard English Conventions makes up about 26% of the Reading and Writing section, which is 11 to 15 of the 50 scored questions.
What's the most tested SAT grammar rule?
Boundaries, meaning how to join or separate clauses with periods, semicolons, commas, colons and dashes. Most of these questions come down to whether each side of the blank is a complete sentence.
Can you learn SAT grammar quickly?
Yes, compared with other question types. The rules are few and consistent, so a week of focused practice often turns grammar into some of the most reliable points on the test.
Sources
- College Board: Assessment Framework for the Digital SAT Suite (PDF)
- College Board: Digital SAT Suite specifications overview (PDF)
Dates, policies and test details change. Check the official source before you make a decision.
