A clause is a group of words that contains a subject and a verb that have a relationship. This relationship is crucial; a clause conveys information about what that subject is or is doing, rather than simply being a random grouping of words. Because a clause expresses an action or a state of being, a clause can often—but not always—function as an independent sentence.
A sentence can have just one clause or it can have multiple clauses. The only defining characteristic of a clause is that it must contain a related subject and verb. Clauses play a variety of roles in English and because of this, there are numerous ways to structure and combine them.
Although you use clauses in your speech and writing every day, it can be easy to overlook the intricacies of clauses in English. Read on to learn how clauses are classified, the roles clauses play in sentences, how to combine clauses to express your thoughts, and the difference between independent and dependent clauses.
Classifying clauses in English
When it comes to expressing a complete thought, a clause falls between a phrase and a sentence. In many cases, a clause can function as its own sentence. A phrase, in contrast, can’t. Here’s a quick look at the difference between a phrase and a clause:
- Phrase: Meows so loudly
- Clause: That cat meows so loudly
In this example, the clause can be an independent sentence. It can also be part of a complex sentence. For example:
- That cat meows so loudly when she wants to eat.
How do clauses in English work?
Clauses can perform three distinct functions: They can operate as adverbs, adjectives, or nouns.
Here’s an example of a noun clause:
- She completely understood everything he said.
In this example, everything he said is a dependent clause that acts as a noun because it communicates the specific “thing” that she, the subject of the sentence, understands. Everything he said can be replaced with his explanation and the sentence still makes perfect sense:
- She completely understood his explanation.
To test whether a clause is a noun clause, try swapping it out for a noun. If your sentence still makes sense, you’ve got a noun clause. Here are two more examples of noun clauses illustrated through swapped-in nouns:
- They remembered what the keynote speaker covered.
- They remembered the keynote speaker’s presentation.
- I don’t know how the company handles onboarding.
- I don’t know their onboarding process.
Just like a noun clause is a clause taking on a noun’s role, an adverbial clause is a clause acting as an adverb. For example:
- She fixed the sink without facing difficulty.
- She fixed the sink easily.
- They spent four years living outside the United States.
- They spent four years living abroad.
- The pool was installed after they built the deck.
- The pool was installed later.
Based on the other two categories, we bet you can guess how an adjective clause works. In case you can’t, here it is: An adjective clause acts as an adjective in its sentence. Here are a few examples with adjectives swapped in to illustrate them:
- My friend who rides a motorcycle said it’s a great weekend to ride.
- My motorcyclist friend said it’s a great weekend to ride.
- No matter what time of day we visit, we always run into the dog that barks.
- No matter what time of day we visit, we always run into the loud dog.
Types of clauses
An independent clause is a clause that can stand on its own as a distinct sentence. Take a look at these examples:
- I love eating cookies.
- My dog barks a lot.
- The kids ate lunch.
- His truck is green.
As you can see, independent clauses aren’t long or complex sentences. They can certainly be part of complex sentences, but by definition, they are known as simple sentences. Other types of sentences include complex sentences, compound sentences, and compound-complex sentences. Each type of sentence is created by a unique combination of independent and dependent clauses. We’ll get into the ways to combine clauses to create different kinds of sentences shortly.
In contrast, a dependent clause is not a complete sentence. Dependent clauses are sometimes known as subordinate clauses. As their name implies, these clauses depend on independent clauses to clearly express ideas. Here are a few examples of dependent clauses:
- When I grow up
- Although he sings well
- The mouse that was hiding
To turn these dependent clauses into full sentences, you need to combine them with independent clauses:
- When I grow up, I want to be a doctor.
- Although he sings well, he hates karaoke.
- I searched through the basement and found the mouse that was hiding.
Take a look at these three sentences and see if you can pick out the differences between the first two and the last one.
In the first two examples, the dependent clause comes before the independent clause and the two clauses are separated by commas. Keep this in mind when you’re writing: Whenever the dependent clause comes first in a complex sentence, it’s followed by a comma.
How to combine clauses
When you want to write a sentence that’s more than one independent clause, you need to combine clauses. Every sentence you write includes at least one independent clause. The other clauses in your sentence determine how you can combine them with your independent clause.
A sentence that includes two or more independent clauses is known as a compound sentence. In a compound sentence, the clauses are joined by a comma paired with a coordinating conjunction, a semicolon, or a colon. This kind of combination is known as coordination. Take a look at these examples of compound sentences:
- I love drinking soda, but I know it’s bad for my teeth.
- Maria loved hosting dinner parties; her friends enjoyed her cooking.
- We danced until the band finished playing: they played until midnight.
When all of your clauses are independent clauses, you can combine them using a coordinating conjunction. In English, the coordinating conjunctions are:
If you need to combine a dependent clause with an independent clause, you need a subordinating conjunction. There are a lot more subordinating conjunctions than there are coordinating conjunctions, and they can be divided into categories according to their function.
A sentence that includes an independent clause and one or more dependent clauses is known as a complex sentence, and a sentence that includes two or more independent clauses and at least one dependent clause is known as a compound-complex sentence. In either of these kinds of sentences, the subordinating conjunction signifies the beginning of the dependent clause. Here are a few examples:
- The fun can begin now that the clown is here.
- While we slept, the plane reached its destination.
- Before you leave, remember to take a goodie bag!
- The pool is open daily until the temperature drops.
As you can see in these examples, when the dependent clause comes first, it needs to be followed by a comma.
Subordinating conjunctions aren’t the only way to add a dependent clause to a sentence. Dependent clauses can also start with relative pronouns or relative adverbs.
Relative pronouns include that, whose, whom, who, and which. Take a look at how these dependent clauses that begin with relative pronouns work in sentences:
- The guy who shouted all night made it impossible to fall asleep.
- Pac’s, that restaurant with the arcade, is the best restaurant in town.
Relative adverbs include where, when, how, and why. Here are a few relative adverb-led dependent clauses at work:
- The traffic jam is the reason why we were late.
- I have no idea when my hose stopped working.
Go beyond the basics of clauses
How can you tell if you’re creating and combining clauses effectively? Give your written work a run-through with Grammarly. Our writing suggestions catch syntax mistakes, awkward phrasing, punctuation errors, and even whether your tone is working for the kind of writing you’re doing.
This article was originally written in 2016 by Shundalyn Allen. It’s been updated to include new information.