Solving Boundaries Questions on the SAT

The method: Find the clauses

Boundaries is clause accounting. If you can spot what can stand alone as a sentence, punctuation choices stop feeling mysterious.

Use Find → Diagnose → Join legally. Mark independent clauses (subject + finite verb, complete thought) and dependent clauses/phrases. If you have two independents, you may join them with a period, a semicolon, or a comma plus FANBOYS (for, and, nor, but, or, yet, so). A comma alone between independents is a comma splice. Connecting nothing but a dependent piece with a period creates a fragment.

Punctuation that joins or separates

Period: full stop between independents. Semicolon: closely related independents; also before conjunctive adverbs like however when they join clauses (…; however, …). Comma + FANBOYS: independents with a coordinating conjunction. Colon: independent clause, then an explanation, list, or amplification. Dash: often pairs like commas for an interrupter, or acts like a colon for an emphatic reveal.

Spot the traps in the choices

The SAT loves offering a comma splice next to a correct semicolon, or a fragment next to a clean period. Also watch double punctuation and “comma + however” without the semicolon that however needs when it joins clauses.

Colons, dashes, and lists

Before a colon, you almost always need a complete independent clause (“She packed three things: …”), not “She packed: …”. Dashes can set off an interrupter — like this — when commas would also work. Don’t mix a dash and a comma to close the same interrupter.

Practice until it’s automatic

Practice questions

Here are five practice problems that help you hone your skills. Use the same method we learned earlier above to solve these problems. Remember, practice makes perfect.