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.
Ada Lovelace whose notes on the Analytical Engine included the first published algorithm remains a foundational figure in computer science.
Which choice fixes the punctuation error?
D — Lovelace, whose notes on the Analytical Engine included the first published algorithm,. 'Whose notes on the Analytical Engine included the first published algorithm' is a nonrestrictive clause that must be set off by commas on both sides. Choice D correctly adds commas both before 'whose' and after 'algorithm.'
The instructor recommended three exercises for beginners squats, lunges, and planks.
Which choice fixes the punctuation error?
B — beginners: squats,. A colon correctly introduces the list of three exercises following the complete independent clause 'The instructor recommended three exercises for beginners.' A comma or semicolon would not properly perform this function.
Three colors dominate the mural, deep blue, burnt orange, and pale yellow.
Which choice fixes the punctuation error?
D — mural: deep. A colon is used to introduce a list following an independent clause, which is what's needed here ('Three colors dominate the mural' is complete, followed by a list of the three colors). Choice D correctly uses a colon; a comma or semicolon would not properly introduce the list.
Three factors shaped the festival's design, local history, community feedback, and available funding.
Which choice fixes the punctuation error?
C — design: local. A colon is used to introduce a list following an independent clause, which is what's needed here ('Three factors shaped the festival's design' is complete, followed by a list of the three factors). Choice C correctly uses a colon; a comma or semicolon would not properly introduce the list.
The town's oldest theater closed for renovation last spring, it will reopen sometime before the holiday season.
Which choice fixes the sentence boundary error?
A — spring. It. The original is a comma splice joining two independent clauses with only a comma. Choice A correctly separates them into two sentences with a period; choice D adds an unnecessary comma after 'and.'
Researchers have identified several risk factors for the disease: family history, prolonged exposure to certain chemicals, and chronic inflammation.
Which choice maintains the sentence's correct punctuation?
B — NO CHANGE. The sentence correctly uses a colon to introduce a list of risk factors following a complete independent clause. No change is needed; the other options would create a comma splice, an improper semicolon use, or an unnecessary sentence break before a list.
The architect's original blueprint, discovered decades after the building's demolition was recently donated to a local historical society.
Which choice fixes the punctuation error?
B — demolition, was. 'Discovered decades after the building's demolition' is a nonrestrictive phrase interrupting the sentence and needs a comma on both sides. The comma after 'blueprint,' is already present, so a matching comma is needed after 'demolition' before 'was.' Choice B supplies this.
The observatory, which was built in 1889 remains in active use by university astronomers today.
Which choice fixes the punctuation error?
C — 1889, remains. 'Which was built in 1889' is a nonrestrictive clause set off by a comma after 'observatory,' and requires a matching comma before 'remains' to properly close the interruption. Choice C supplies this.
Researchers have identified several factors that influence coral bleaching: rising ocean temperatures, increased acidity, and pollution from agricultural runoff.
Which choice maintains the sentence's correct punctuation?
D — NO CHANGE. The sentence correctly uses a colon to introduce a list of factors following a complete independent clause. No change is needed; the other options would create a comma splice, an improper semicolon use, or an unnecessary sentence break before a list.
The trainer recommended three drills for new swimmers kicking, breathing, and arm rotation.
Which choice fixes the punctuation error?
D — swimmers: kicking,. A colon correctly introduces the list of three drills following the complete independent clause 'The trainer recommended three drills for new swimmers.' A comma or semicolon would not properly perform this function.
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.