SAT Grammar 1: Sentence Boundaries and FragmentsSAT Grammar 1: Sentence Boundaries and Fragments

S A T R E A D I N G A N D W R I T I N G · GRAMMAR

Sentence Boundaries and Fragments

SAT Grammar Guide 1

Goal: Decide whether a group of words is a complete sentence, then join or separate sentences with correct punctuation.

Original study notes on standard SAT grammar and punctuation rules, with original examples. Not copied from any prep book.

Big Picture

Many SAT grammar questions are really boundary questions: is this a complete sentence, and how is it connected to the next one? If you can spot an independent clause, you can answer most of them. The Building Blocks

Unit Has subject + verb? Can stand alone? Example

Independent clause (IC) Yes Yes The museum opened early.

Dependent clause (DC) Yes, but starts with a subordinating word No Because the museum opened early Phrase No complete subject + verb pair No Opening early on weekends

Subordinating words that make a clause dependent include although, because, if, since, unless, when, while, after, before, which, who, that.

Fragments

A fragment is missing a subject, missing a real verb, or is a dependent clause trying to be a sentence. Dependent clause alone: "Although the team practiced daily." Fix: attach it to an IC: "Although the team practiced daily, it lost."

-ing word with no helping verb: "The gardener working in the yard." Needs a real verb: "The gardener was working in the yard."

Missing subject: "And then ran to the station." Add who ran.

Trap: a long sentence that never reaches a real verb because everything is a descriptive phrase. Correct Ways to Join Two Independent Clauses

Method Pattern Example

Period IC. IC. The bridge closed. Traffic backed up.

Semicolon IC; IC The bridge closed; traffic backed up.

Comma + FANBOYS IC, for/and/nor/but/or/yet/so IC The bridge closed, so traffic backed up. Colon IC: explanation Traffic backed up: the bridge closed.

Dash IC — explanation Traffic backed up — the bridge had closed.

Subordinate one DC, IC or IC DC Because the bridge closed, traffic backed up.

The Two Classic Errors

Comma splice: IC, IC with no conjunction. "The bridge closed, traffic backed up."

Run-on (fused sentence): IC IC with no punctuation. "The bridge closed traffic backed up." Conjunctive adverbs do not fix splices. Words like however, therefore, moreover, consequently, thus, nevertheless cannot join two ICs with only a comma. Use a semicolon before them: "The test was hard; however, most students passed."

Fast Method

Cover the punctuation and test each side: can it stand alone as a sentence?

If both sides are ICs, you need a period, semicolon, colon, dash, or comma + FANBOYS. If one side is a DC or a phrase, a single comma (or no punctuation) usually joins it. If you see a period followed by an -ing phrase or a "which" clause, suspect a fragment. Key Terms

Term / Actor What it is and why it matters

Independent clause Subject + verb that expresses a complete thought.

Dependent clause Subject + verb introduced by a subordinating word; cannot stand alone. Fragment Incomplete sentence: no subject, no real verb, or a lone dependent clause. Comma splice Two ICs joined by only a comma.

Run-on Two ICs with no punctuation or conjunction.

FANBOYS For, And, Nor, But, Or, Yet, So: coordinating conjunctions used after a comma to join ICs. Making This Essay-Ready

Practice habit: For every underlined punctuation mark, label the words on each side IC, DC, or phrase before choosing.

Common trap: A long subject or a parenthetical can hide the main verb, making a complete sentence look like a fragment.

SAT Grammar Guide 1 · Original SAT grammar study notes