One thing I hear time and time again is that students think they need to be grammar experts for the ACT English test. And every time, I say this is not true!

The ACT aims to test a very specific skillset when it comes to the English language, and one thing you will without a doubt be tested on is comma usage. Still a little worried? Don't be! I've got a handy guide you can use to help master this skill before the big day arrives!

Because the ACT will only present you with four different reasons to use a comma, keeping these in mind during your ACT prep will get you well on your way to becoming a comma expert.

Creating a List of Three or More Items

If the ACT gives you a list of three or more items, always use a comma, placing it in front of the “and" that comes before the final item. This isn't something that everyone agrees on, but the ACT wants your writing to be four things— complete, consistent, clear, and concise — and using that last comma will always make your writing clear. Here's an example:

Marilyn invited the dancers, John and Joe.

Without a comma before “and," this sentence means that John and Joe are the dancers that Marilyn invited.

Marilyn invited the dancers, John, and Joe.

Now, the sentence means that Marilyn invited three separate parties: the dancers, John, and Joe.

Note that the first version without the comma before the “and" could be interpreted as the second. But the ACT doesn't like this (it isn't clear), so you'll never need to determine whether John and Joe were the dancers. Go with the comma before “and" in a list of three or more things!

“Stop" Punctuation

Think of the punctuation mark you are able to use most confidently. What comes to mind? I'm guessing quite a few of you would shout “the period!" because it's the most straightforward to use correctly. I totally get it! But the writers of the ACT won't take that as an excuse to avoid using commas, and one of those situations is in place of a period. We call this “Stop" punctuation.

Consider the following (incorrect) sentence:

John was worried his friends would disapprove of his outfit he texted them in advance to warn them.

This sentence contains two complete ideas that could form separate sentences — if properly connected. The connection is what is missing in the above example. An option to fix it would be to insert a period between “outfit" and “he," but that's not the only way to do it. (And the ACT expects you to know an alternative!) So where does a comma come in? Well, another choice to fix the above sentence is to combine a comma and a coordinating conjunction in the same place you'd use a period.

Wait, wait, wait. What's a coordinating conjunction, you ask? Those are going to be words like for, and, nor, but, or, yet and so. (You can remember these as FANBOYS.) Using this method to fix the sentence looks like this:

John was worried his friends would disapprove of his outfit, so he texted them in advance to warn them.

Since you could technically stop the sentence at this point where you're inserting a comma along with one of the FANBOYS, we call this use “Stop" punctuation. This rule can be tricky, so look out for it on the ACT!

“Go" Punctuation

You might see a sentence that doesn't contain two complete ideas — there might be one complete idea and one incomplete — and these can be connected by a comma. Here's an example:

After the performance ended, viewers who didn't purchase tickets heard great reviews from their friends.

Here, “after the performance ended" is incomplete, so you must use a comma to link that idea to what follows, which happens to be a complete thought. Since there is no correct way to stop the first clause of the sentence, we call this “Go" punctuation.

Setting off Unnecessary Info

Most information that is added to a sentence modifies the meaning of a word, changes the structure for effect or emphasis, or adds critical information. But sometimes, we wish to add in details that aren't essential. (We're all fans of a little exaggeration, right?) But it's important to remember that if we're going to use any unnecessary info, we should set it off from the rest of the sentence by using a pair of commas. Here's an example:

A pair of commas, which look like little boomerangs, can be used to set off words that don't alter the meaning of a sentence.

Don't let a question trick you — if you can't justify using a comma in one of these four ways, the ways that are tested on the ACT, then one isn't needed! (Even that sentence uses one of the four rules mentioned above: setting off unnecessary information!) That's what the “NO CHANGE" option is there for: If the answer choices are suggesting ways to add an unnecessary comma, just pick NO CHANGE.

If you want more grammar coverage before the big day, check out guides like our English and Reading Workout for the ACT. Using guides that offer what you need to know, while also showing you the best ways to go about applying that information, are crucial in effective ACT prep.