This Magoosh ACT science test is very, very important because it is about perhaps the most important category of grammar that is tested by the ACT, and that is the comma. There are so many questions on commas on this test. So it's a really, really important video to be paying extra special attention to, if you struggle with commas at all. Show Transcript
So let's start by going over the three major uses of commas. So the first major use of a comma is to set off a dependent or a subordinate clause. Now, I know I'm using this technical language here dependent and subordinate clause, you don't actually have to know what they're called on ACT, you just need to know how to recognize them.
I'm using them here for a3 simplicity and, and creating a list of things that commas are used for. But we're gonna go through some examples, so don't worry, you'll be able to see what I mean in just a moment. The second major use of a comma is to create a compound sentence with a conjunction, specifically what's called a coordinating conjunction.
And we will go through specifically what the coordinating conjunctions are in a minute. Again, you don't need to know what they're called. You just need to know how to recognize them. And finally, the third major use of a comma is one you see all the time, and that is to separate lists of items.
So let's talk about number one first. Setting off dependent or subordinate clauses. So there's a few different type of clauses. Again, I'm using the terms here just in case you want to geek out in grammar a little bit with me or just to help create some clarity in categories here, but you don't need to know what they're called.
You need to focus primarily on the examples and that will be just fine, for the purpose of the ACT. So we can use commas to set of what are called appositives, now, appositives are pretty important to an everyday ACT, because your gonna see that tested hm, probably at least a couple times in every test. And an appositives is a noun or a noun phrase that renames another noun.
So for example, my cat, a purebred Persian, acts like a feral dog. So a purebred Persian. Purebred Persian renames cat here. It describes it. And we're setting it off with commas because it's extra information that adds to the sentence but it's not essential to it.
So the sentence could be, my cat acts like a feral dog. But what creates, you know, a little bit of humor, or a little bit of irony in this situation, is the fact that it's a purebred Persian. So the writer wants to put that in to say my cat, even though it's a purebred Persian, still acts like a feral dog. So we're setting them off with comma, since it's extra information.
The second category of a clause that could be set off with commas here, is the particip, participial phrase. Let's look at an example. Looking every bit like a madman, my brother leapt from his bed and raced out the door once he realized he overslept for his exam. So, this is a phrase that starts a sentence describing my brother.
Now, this is something you'd also wanna be watching out for when you are dealing with a misplaced modifier question. Because whatever comes before the main part of the sentence, this phrase here, needs to describe what starts the main part of the sentence, so in this case it's correct. My brother is looking every bit like a madman, but because that's extra bit of information set off at the beginning of the main part of the sentence, which starts with my brother, it is set off with a comma.
Commas help us take pauses, take a break, take a breath. And so when I read the sentence we have, looking every bit like a madman, my brother leapt from his bed. It's natural, we wanna take a pause there, so we're not just running all our words together and losing track of, losing the clarity of the sentence. So another comma used, setting off a clause here.
It is setting off a subordinate clause. So, for example, until I carefully checked under the covers for spiders, my sister refused to get out of bed. So, this is something that needs to happen before my sister gets out of bed, until I carefully checked under the covers for spiders, so again, what's important here is not necessarily what it's called, but the fact that we have a main part of the sentence that can stand alone as a sentence.
My sister refused to get out of bed, or get into bed, but I eh, need to carefully check under the covers for spiders and she's not gonna do that until I do that so that's some extra information that helps describe why my sister is refusing to get into bed. And then we have relative clause again. So for example, I carefully checked under the covers for my sister, who was deathly afraid of spiders.
So this is a modifier, it's describing the sister. The sister is deathly afraid of spiders. But again, the important thing is we have a main part of a sentence here that can stand alone as a sentence. I carefully checked under the covers for my sister. And then we have some extra information we wanna add to describe that sister, and it needs to be set off with a comma in all of these instances.
Okay, so I want to bring up something important here and that is commas with which, that, and who. Because this is something you'll also, the wondering about on the test. So you should use commas before which but not before that. So for example, those movies, which I've never even attempted to watch, are my sister's favorites.
But the movies that are my favorites are the ones with lots of action in them. So why is there a difference here? The reason is because which is used to set off information that's considered to be not essential to the fundamental meaning of the sentence. But use that when it is essential to the sentence. So back to this first example, those movies, which I've never even attempted to watch, are my sister's favorites.
In this case, the author's considering it to be, you know, kind of extra information, not essential to the meaning of the sentence. In the second one, we want to be sure, or the writer wants to be sure that the reader knows that the movies that are my favorites, his favorite movies, or her favorite movies, are the ones with lots of action in them, so this is essential. It's essential information to the meaning of the sentence, and so we use that.
Because which is used to set off non-essential information, then we set it off with a comma, or commas, because remember, when you set thing off with commas, you're basically saying this is some extra information I'm adding into the sentence. Now when you have who, it's a little bit trickier. It depends on whether or not the description is essential.
So for example, the teacher who has always been my favorite decided to retire this year. Were my teacher, who has never been a stickler for rules, lets us throw paper around the room and dance on our desks. So with who, you're making a decision about whether or not it's essential or not.
There's not a hard and fast grammar rule for it. But don't worry the ACT is not gonna ask to make decisions about what's essential information or what's not essential information ever on the test regardless of whether it's which, that, or who. But it will ask you to punctuate that correctly. So, if we have which we need to have a comma before it.
If we have that, we do not want a comma before it. And with who, it could go either way. All right, so let's talk about the second big category of comma usage now, and that is to create compound sentences. So when you use a comma and what's called a FANBOY, this is an acronym to help you remember for, and, nor, or, but, yet, or so.
You wanna memorize these conjunctions. And the reason is because the ACT will often put another word after a comma that is not one of these FANBOYS and that would make it wrong. So you really wanna make sure you know what these seven conjunctions are that can be used to create a compound sentence. So for example, here is a correct use of a comma and conjunction.
I've never been one for studying grammar, so I overlooked that part of my ACT preparation. So here we have a comma and we have one of the FANBOY conjunctions. Now most students, and, and, but or, or are used a lot more frequently and so they know those are conjunctions, so don't forget about for, yet, and so. Those are also coordinating junctions.
Here's something that would be wrong and this is something that the ACT definitely tests. I've never been one for studying grammar, therefore I overlooked that part of my ACT preparation. Therefore is a transition, but it is not one of these FANBOYS, and therefore you can't link two sentences that could stand alone with therefore.
So this would be wrong, this would be a comma splice, not a correctly constructed compound sentence. All right. Let's go on to number three, and that is to separate lists. So for example, fishing, hiking, and camping are my favorite summer activities. Now sometimes students want to know if they should have a comma here or not.
Whether there's a comma there or not has to do with American versus British English styles. The ACT won't test you on that, so don't worry about that aspect of it. Just make sure you are effectively setting off a list with commas. Let's take a look at a sample test question testing comma usage in a list. Most large retailers post their Black Friday ad scans, coupons, and offers online to give consumers time to find out about sales and plan their purchases.
Okay, so this sentence is testing commas. It's testing commas, specifically, in a list because we do have a list of things here. We have ad scans, coupons, and offers. But what it is testing is what's supposed to go on this list. We've got this weird comma here.
Is offers online to give, is that one thing that's supposed to go on the list, and then consumers is another thing that's supposed to go on the list? Mm, I don't think so. So let's take a look and see if we can punctuate this correctly. So answer choice B has ad scans, coupons, and offers, online to give. Now there's no comma here, but remember that A, C is not gonna necessarily test you on it.
What makes this wrong although it usually will put that comma there. What makes it wrong though is that fact that this comma here is being placed between offers and online. So we don't wanna have a comma there, that's just separating the subject, from the verb awkwardly. We want to make sure that this list is properly separated.
Ad scans, coupons, and offers online to give consumers time, so we don't wanna have a weird comma elsewhere. And so that means our answer is D, which properly punctuate that list with commas. So, once again, the three major uses of commas. To set off dependent or subordinate clauses. Let's just call that setting off clauses.
Setting off bits of information that are extra to the main part of the sentence. Remember, what's set off by commas whether it's at the beginning, the end, or in the middle always needs to be able to be lifted out of the sentence, and we should still have that main part of the sentence there. Two, to create compound sentences with a coordinating conjunction, remember those are your FANBOYS, memorize those seven conjunctions.
And finally, and for a lot of students, this is the easiest one, to separate lists.