SAT Reading and Writing Practice
Boundaries

Apply correct punctuation, including commas, semicolons, and colons, at the boundaries between clauses and phrases.

58 original boundaries questions in the SAT Ranker bank, with instant scoring and an Elo-based rank once you sign up. Below are a few free samples with full explanations.

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Sample question 1 · easy

Which choice is punctuated correctly?

The lecture ran long the students, growing restless, began packing their bags.
The lecture ran long, the students, growing restless, began packing their bags.
The lecture ran long; the students growing restless began packing their bags.
The lecture ran long; the students, growing restless, began packing their bags.

Two independent clauses need a semicolon between them, and the nonessential phrase 'growing restless' needs commas on both sides. Only the version carrying both the semicolon and the paired commas does that.

Sample question 2 · medium

Sequencing the genome took thirteen years and cost nearly three billion dollars ______ today the same work takes an afternoon and costs less than a bicycle.

Which choice completes the text so that it conforms to the conventions of Standard English?

,
: but
but,
;

Two independent clauses stand side by side with no conjunction between them, which calls for a semicolon. A comma alone would splice them, ' but,' misplaces the comma after the conjunction, and ': but' pairs a colon with a conjunction.

Sample question 3 · medium

Hedy Lamarr ______ better known in her lifetime as a film actor, co-patented a frequency-hopping system that anticipated modern wireless communication.

Which choice completes the text so that it conforms to the conventions of Standard English?

;
,
:
who was

'Better known in her lifetime as a film actor' is a nonrestrictive phrase describing Lamarr, and the comma after 'actor' shows it is being set off, so a matching comma is needed before it. A semicolon or colon would require a complete clause on at least one side, and ' who was' would leave a single comma standing between the subject and its verb 'co-patented', which is not allowed.

Sample question 4 · medium

Which choice is punctuated correctly?

The committee reached a decision, three of the five original proposals would move forward.
The committee reached a decision three of the five original proposals would move forward.
The committee reached a decision; three of the five original proposals would move forward, though.
The committee reached a decision: three of the five original proposals would move forward.

A colon correctly introduces the specific decision that follows a complete independent clause. The comma splice, unnecessary semicolon-plus-'though,' and missing-punctuation options are all incorrect.

Sample question 5 · hard

The recipe survives in a single source ______ a household ledger kept by a cook who never intended it to be read.

Which choice completes the text so that it conforms to the conventions of Standard English?

which,
;
and,
:

'The recipe survives in a single source' is a complete clause, and what follows identifies that source, so a colon is appropriate. A semicolon requires an independent clause after it, and the other options are ungrammatical.

More topics
SAT Reading and Writing skills
Words in ContextCentral Ideas and DetailsCommand of EvidenceInferencesText Structure and PurposeCross-Text ConnectionsRhetorical SynthesisTransitionsForm, Structure, and Sense