10 original Boundaries questions, easiest first. Where sentences end, and which punctuation may join what. Answer them all, then submit once to see every answer explained.
The town's water tower closed unexpectedly for repairs last week, it will resume normal service once the necessary parts arrive.
Which choice fixes the sentence boundary error?
B — week. It. The original is a comma splice joining two independent clauses with only a comma. Choice B correctly separates them into two sentences with a period; choice D adds an unnecessary comma after 'and.'
The cafe's menu lists five seasonal drinks, however, only three remain available after October.
Which choice fixes the sentence boundary error?
D — drinks; however, only. 'However' here connects two independent clauses and needs a semicolon (or period) before it, with a comma after. Choice D correctly uses a semicolon before 'however' and a comma after it, fixing the comma splice in the original.
The novel's plot unfolds across three timelines, the 1920s, the 1960s, and the present day.
Which choice fixes the punctuation error?
B — timelines: the. A colon is used to introduce a list following an independent clause ('The novel's plot unfolds across three timelines' is complete, followed by a list of the three timelines). Choice B correctly uses a colon; a comma or semicolon would not properly introduce the list.
The sculptor's unfinished commission, delayed by a shortage of bronze was ultimately completed a year behind schedule.
Which choice fixes the punctuation error?
C — bronze, was. 'Delayed by a shortage of bronze' is a nonrestrictive phrase interrupting the sentence and needs a comma on both sides. The comma after 'commission,' is already present, so a matching comma is needed after 'bronze' before 'was.' Choice C supplies this.
The composer's unfinished opera, abandoned midway through its second act was completed decades later by one of his former students.
Which choice fixes the punctuation error?
A — act, was. 'Abandoned midway through its second act' is a nonrestrictive phrase interrupting the sentence and needs a comma on both sides. The comma after 'opera,' is already present, so a matching comma is needed after 'act' before 'was.' Choice A supplies this.
The museum's east wing, closed for asbestos removal will reopen to visitors sometime next spring.
Which choice fixes the punctuation error?
B — removal, will. 'Closed for asbestos removal' is a nonrestrictive phrase interrupting the sentence and needs a comma on both sides. The comma after 'wing,' is already present, so a matching comma is needed after 'removal' before 'will.' Choice B supplies this.
Rachel Carson whose book Silent Spring helped launch the modern environmental movement remains an influential figure decades after her death.
Which choice fixes the punctuation error?
A — Carson, whose book Silent Spring helped launch the modern environmental movement,. 'Whose book Silent Spring helped launch the modern environmental movement' is a nonrestrictive clause that must be set off by commas on both sides. Choice A correctly adds commas both before 'whose' and after 'movement.'
Although the pilot survey produced encouraging results the analysts cautioned that a larger sample would be needed before any policy change.
Which choice fixes the punctuation error?
B — results, the analysts. 'Although the pilot survey produced encouraging results' is a dependent introductory clause that requires a comma before the main clause begins. Choice B correctly adds this comma.
Despite months of extensive testing the software update was pulled from release after users reported a critical security flaw.
Which choice fixes the punctuation error?
A — testing, the software. 'Despite months of extensive testing' is an introductory phrase that requires a comma before the main clause. Choice A correctly adds this comma; a semicolon or colon would be used to join independent clauses or introduce a list/explanation, neither of which applies here.
The county's oldest courthouse closed for restoration last winter, it will reopen sometime before the fall term of court.
Which choice fixes the sentence boundary error?
B — winter. It. The original is a comma splice joining two independent clauses with only a comma. Choice B correctly separates them into two sentences with a period; choice A adds an unnecessary comma after 'and.'
Score:
Every question above is now marked up: the correct answer is highlighted, any wrong option you picked is flagged, and each explanation is open.
No. Every question here is original, written to the College Board's published Digital SAT Reading & Writing specification for the Boundaries skill. No retired or copyrighted College Board material appears anywhere on this site.
Boundaries tests sentence boundaries and the punctuation that marks them: periods, semicolons, colons, commas, and dashes, including comma splices, run-ons and the punctuation around supplementary elements. Every question is answerable from the sentence in front of you, without knowing anything about the subject matter.
Ignore how the sentence sounds and test the structure instead. Decide whether the material on each side of the punctuation is an independent clause — a subject and a verb that could stand alone. Two independent clauses need a period, a semicolon, or a comma plus a coordinating conjunction; a colon needs an independent clause on its left; a supplementary phrase needs the same mark on both sides, and never a comma on one side and a dash on the other.
No, and deliberately so. This drill is 10 Boundaries questions back to back; a real Reading & Writing module is 27 questions in 32 minutes drawn from all eleven skills. Use a drill to fix one weakness, then take a full module to practice the real thing.
No. The SAT has no penalty for a wrong answer — a blank and a wrong guess both score zero — so answer every question, including the ones you have to guess.