Grammar Guide: Supplements - Study SAT-ACT-EST Online Academy

A guide to supplementary phrases on the SAT.

What are supplements?

Supplements are words, phrases, and relative clauses that add extra information to a sentence, often for the purpose of description or elaboration. There are two main types of supplements:

Essential elements are necessary for the sentence to function and don’t require punctuation. Example

In a basketball game, the team that scores the most points will win.
Without the relative clause “that scores the most points”, we wouldn’t know which “team” the sentence was talking about. If we eliminate this information, the sentence wouldn’t make any sense:
In a basketball game, the team will win.

Nonessential elements are not necessary for the sentence to function. They must be separated from the main sentence by punctuation.

Example:
The basketball team, which won the state championship last year, got on the bus.
The relative clause “which won the state championship last year” adds an interesting description, but it’s not essential to the sentence. If we eliminate this information, the sentence still makes sense:
The basketball team got on the bus.

The SAT / EST Test focuses on whether supplements should be separated from the rest of the sentence by punctuation, as well as what punctuation marks should be used. These conventions may be tested in Boundaries questions that you encounter on test day.

How are supplements punctuated?

There are several factors that govern how supplements should be treated within a sentence. Let’s look at each in turn.

Essential or nonessential

The first question is whether a given supplement should be punctuated. Try reading the sentence without the supplemental information.

If the sentence no longer makes sense, then the supplement is an essential element. No punctuation should be used.
If the sentence still makes sense, then the supplement is nonessential. The supplement must be separated from the rest of the sentence by punctuation.

Position in the sentence

Once you determine a supplement is nonessential, you must decide how to punctuate it.

If the supplement begins or ends the sentence, it only requires one punctuation mark (between the supplement and the rest of the sentence).
If the supplement comes in the middle of the sentence, it requires punctuation on both sides.

Hide example

A striker with 62 goals in international play, Megan Rapinoe is known for her activism in addition to her soccer stardom.

Here, the supplement comes at the start of the sentence, so it only requires one punctuation mark.

Megan Rapinoe, a striker with 62 goals in international play, is known for her activism in addition to her soccer stardom.

Here, the supplement comes in the middle of the sentence, so it must be separated with punctuation on both sides.

Type of punctuation

Nonessential elements can be separated from the rest of a sentence using three different types of punctuation marks:

Commas (,)
Parentheses ()
Dashes (—)

In formatting supplements, these punctuation marks are basically interchangeable. However, there is one important rule: the same type of punctuation must appear before and after a nonessential element.

In other words, we don’t want to be mixing different punctuation marks together.Example

Incorrect:
The male chaffinch—with its blueish cap and rusty red feathering, is more colorful than its female counterpart.
Correct:
The male chaffinch—with its blueish cap and rusty red feathering—is more colorful than its female counterpart.
The male chaffinch, with its blueish cap and rusty red feathering, is more colorful than its female counterpart.
Either dashes or commas can be used to punctuate this supplement, but we can’t use one of each!

How to identify supplements 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 supplements if

the choices add or remove commas, but not conjunctions
the choices include multiple types of punctuation, like commas and dashes

If you don’t see either of these features, then the question likely doesn’t deal with supplements.

Let’s look at a supplements question now:

SUPPLEMENTS EXAMPLE

Luci Tapahonso is the inaugural poet laureate of the Navajo Nation. Her book Sáanii Dahataal/The Women Are Singing—a combination of fiction and memoir, poetry and ______ serves as a testament to her versatility as a writer.

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

Tips & hacks

Top tips
Be consistent!
SAT questions will often include just one side of a nonessential element in the underlined portion of the sentence. Be sure to check the other side of the element for consistency: the same punctuation mark should be used on both sides!
Don’t worry about the difference between commas, parentheses, and dashes
While commas, parentheses, and dashes are sometimes better in particular contexts, the SAT won’t test you on these minor differences. In other words, you’ll never be asked to choose between two types of punctuation marks if the choices don’t create other grammar errors. So don’t sweat it!
Don’t pair semicolons or colons!
Commas, parentheses, and dashes are the only options when separating a nonessential element from the rest of the sentence. We should never use two semicolons or colons around a nonessential element.