Commas and introductory elements | Punctuation | Grammar | Khan Academy

Hello, grammarians! Uh, Paige and I are here to teach you about introductory elements in sentences and how commas relate to them.

Paige, what, how do we—how should we define what an introductory element is?

So, it's pretty much, uh, something that happens at the beginning of a sentence. It can be like a dependent clause or an adverb. Um, but as we will see soon, it is something that is separated off with, of course, a comma because that's what commas do—they are separators.

So, let's talk about dependent clauses first. Let me just write out a sentence that begins with a dependent clause: "When you come in, please take off your shoes."

I've made the difference between the dependent clause and the independent clause pretty clear. So, this is, you know, the dependent clause is purple, the independent clause is green. Um, is there a need for a comma here? Of course! Okay, because we're leading with a dependent clause, that means that this thing can't stand on its own, right?

It's like the ladder up against the tree. Because an independent clause in green can stand on its own, a dependent clause cannot. So, um, we need to differentiate it from the rest of the sentence by putting the comma there.

So, this is a dependent clause, and this is an independent clause. So if you start a sentence with a dependent clause, you're going to need to put the comma in the middle before you proceed to the independent clause, which is the part that makes it an actual functioning sentence.

Right? If you have it the other way around, though, if it's just "Please take off your shoes when you come in," no need for a comma. I'll show you.

So, I'm not sure why this is. Uh, I think it may just sort of be a style relic—I'm not entirely certain. I mean, if you go back in American history and you look at, like, the Federalist Papers and you look at the way the people used commas in the 18th century, it doesn't make a whole lot of sense relative to how we use commas today.

Uh, so a lot of this is cultural. But I can tell you that when an independent clause comes before a dependent clause, you don't use a comma. And if you are uniting two independent clauses in the following sentence: "I wrote an elephant, and then I ate a mango." These two things are both independent clauses, right?

"I wrote an elephant, then I ate a mango." Right? Like these two things, uh, need to be connected by this conjunction "and." But that's not all! They also need to be joined by a comma. Now, you could also sub out if you wanted to, you know, get rid of this comma and this "and" and put in a semicolon, but that's a story for another time.

So if you're uniting two independent clauses, just do comma and then a conjunction. So that's one way to think about how to use commas for introductory elements like dependent and independent clauses.

But there's also another thing I want to introduce you to, and that's sentence adverbs. Follow us over to the next screen.

So, Paige, what is a sentence adverb? How does it work?

So, we've been talking about, you know, starting sentences with clauses, but that doesn't always have to be the case. You can start a sentence with an adverb, like, let's say, "Initially, I was afraid."

So what is "initially" doing in this sentence? Here in this expression, basically, it's modifying like the whole rest of the sentence. It's modifying the "I was afraid." So we're going to put a comma here to separate it from the rest of that expression. That's why we call it a sentence adverb—because it's not the same as saying "I was initially afraid."

This is, kind of like you said, modifying the entire expression. Let's look at another example: "Basically, you're the greatest."

Oh, thanks, Paige! So we've got this word "basically," and basically, it is modifying the entire expression—it's kind of qualifying the whole thing, right? So we're going to put a comma between this sentence adverb and the sentence itself.

Exactly! Cool. So, initially, Paige, this seemed pretty complicated to me, right? But basically, I think we got it down.

All right! We think that essentially, you can learn anything.

David out. Paige out.