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Course: Digital SAT Reading and Writing  > Unit 5

Lesson 8: Boundaries: Punctuation
Test prep
Digital SAT Reading and Writing
SAT Grammar practice
Boundaries: Punctuation
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Grammar guide: Punctuation

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A guide to punctuation on the SAT.

What punctuation marks are tested on the SAT?

Punctuation appears as part of a variety of questions on the SAT. Whether we're linking clauses or adding supplements to a sentence, we'll need to appropriately employ punctuation. We may also need to identify instances where no punctuation is necessary.
The SAT may test your knowledge of
  • Commas (,)
  • Semicolons (;)
  • Colons (:)
  • Dashes (—)
Appropriate punctuation will be essential to all Boundaries questions that you encounter on test day.

Punctuation marks

Different punctuation marks have different uses and different rules. Let's look at each in turn.*
*Note: some punctuation marks have additional uses not named here (e.g., formatting dialogue with commas). This article focuses only on how these punctuation marks are tested on the SAT.

Commas (,)

Commas should only be used to...
  • Separate list items
  • Separate nonessential elements from the sentence
  • Link dependent clauses to independent clauses
  • Link independent clauses with help from a coordinating (FANBOYS) conjunction
Commas should not...
  • Split a subject and a verb
  • Come before
  • Separate items in a list of two
Using a comma in any of these ways creates an error.

Semicolons (;)

Semicolons should only be used to...
  • Link independent clauses (without a conjunction)
  • Separate list items that already contain commas
Any other use of a semicolon creates an error.

Colons (:)

Colons can only come at the end of an independent clause. They can introduce...
  • Explanations and extra information
  • Lists
Any other use of a colon creates an error.

Dashes (—)

Dashes should only be used to separate nonessential elements from the rest of the sentence.
Any other use of a dash creates an error.

How to identify punctuation questions

When approaching boundaries questions, it's important to identify which Standard English conventions are being tested.
You may want to look for errors in punctuation if
  • the choices add or remove punctuation
  • the choices offer a variety of punctuation marks
If you don't see either of these features, then the question likely doesn't deal with punctuation.
Let's look at a punctuation question now:
Punctuation example (supplements)
According to Naomi Nakayama of the University of Edinburgh, the reason seeds from a dying dandelion appear to float in the air while ______ is that their porous plumes enhance drag, allowing the seeds to stay airborne long enough for the wind to disperse them throughout the surrounding area.
Which choice completes the text so that it conforms to the conventions of Standard English?
Choose 1 answer:

Top tips

Use the before/after test for semicolons

Unless it appears in a list, a semicolon must have an independent clause both before and after it. If you think a semicolon might be right, check to make sure you have an independent clause on either side. If you don't, you can't use a semicolon.

Use the before test for colons

A colon can only appear at the end of an independent clause. If you think a colon might be right, check to make sure what comes before is a complete independent clause. If it's not, you can't use a colon.

Double-check commas

Many writers overuse commas (or use them as a default punctuation mark). Double-check to make sure a comma is both necessary and appropriate before selecting it as your answer.
If the comma is linking clauses, make sure it has the coordinating or subordinating conjunction it needs to do so.
If the comma isn't linking clauses, make sure it serves a purpose and doesn't unnecessarily interrupt some other function of the sentence.

Your turn

Punctuation
An element's atomic number is ______ the number of protons in its nucleus, the number electrons in its uncharged state, and approximately half of its atomic mass.
Which choice completes the text so that it conforms to the conventions of Standard English?
Choose 1 answer:

Punctuation
When he returned from the Galapagos islands in 1835, Charles Darwin brought back a young tortoise named ______ would live over 170 years before passing away at the Australia Zoo in 2006.
Which choice completes the text so that it conforms to the conventions of Standard English?
Choose 1 answer:

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