Complex sentences | Syntax | Khan Academy

Hello grammarians! Hello Rosie! Hi Paige!

So in this video, we're going to talk about complex sentences. We've talked in another video about simple and compound sentences. So that is like one independent clause or two independent clauses. With a complex sentence, we're going to introduce something called a dependent clause.

A sentence needs at least one independent clause to function as a sentence, but with complex, we're going to add this dependent clause. So, Rosie, what's an example of a complex sentence?

"When we buy his birthday cake, we have to make sure it's lemon." So this sentence, "When we buy his birthday cake, we have to make sure it's lemon," is made up of two clauses, and I've written them in different colors here.

So this second one, the pink one, can stand on its own as a sentence. We could just say, "We have to make sure it's lemon." It works; it functions as an independent clause, as its own sentence.

We have some information that might be missing from this sentence because we don't necessarily know what "it's" is. But we do have all the components of an independent clause here. We've got a subject (we) and a verb (have to).

And, well, we have multiple verbs. Yeah, got a lot of "have to make sure." So the sentence is relying on some information that’s not provided, but it does still stand as its own sentence. Right?

Like we could have a sentence before it that's like, "We're going to go buy a birthday cake. We have to make sure it's lemon." Right? Those can be two separate sentences.

In this case, we have this other clause, this what's called a dependent clause. We can't just say, "When we buy his birthday cake," as a sentence. That doesn't really stand on its own. It doesn't convey the information that a sentence needs to convey.

So we could have an independent clause or a sentence that's just, "We buy his birthday cake." It's kind of a weird construction. I don't know that I would say that. You could maybe say, "We are buying his birthday cake," right?

But "We buy his birthday cake" still works as a sentence. It has a subject (we) and a verb (buy), and it expresses a complete idea. It's an action that's happening and it tells you who's doing it.

But we add this thing called a subordinating conjunction. That's this word "when" here, and that makes this into a dependent clause. It can't be a sentence by itself, so it depends on the later clause, "We have to make sure it's lemon," to be part of a sentence.

Okay, so Rosie, what's another example of a complex sentence?

"Although our tent was zipped up, the sound of hyenas in the distance still frightened us." So again, this sentence starts with a dependent clause, "Although our tent was zipped up." This would be independent if it said, "Our tent was zipped up," but again, we have this subordinating conjunction "although" at the beginning.

And there's kind of a whole bunch of different subordinating conjunctions. They're sort of just something that you need to remember. But essentially, their job is to connect clauses in sentences but also make things into dependent clauses.

One other thing, we're showing you two sentences where the dependent clause is coming before the independent clause, but that's not necessarily always going to be the case. Like, for example, we could have said, "The sound of hyenas in the distance frightened us, even though our tent was zipped up." Right? That would still be a complex sentence; it would be an independent clause and a dependent clause, but just in a different order.

They don't have to be in this order that we've done twice.

Okay, so Rosie, what if I do something like this: "When we buy his birthday cake, we have to make sure it's lemon because it's his favorite." I think "because it's his favorite" is a dependent clause, right?

That's right! And this sentence still completely works as a complex sentence because you still just have this one independent clause, "We have to make sure it's lemon."

But the thing about complex sentences is you can add more than one dependent clause if you want, and it's still considered a complex sentence.

Okay, so it has to have just one independent clause, right? But I guess as many dependent clauses as you want?

Yeah, you can go crazy!

Okay, cool! So I think that's complex sentences. It's an independent clause that can be a sentence by itself and one or more dependent clauses, which can't be sentences by themselves all put together in one big sentence.

Does that sound right, Rosie?

Sounds good to me, Paige! Cool! You can learn anything!

Paige out.

Rosie out.