Clause

What Is a Clause?

A clause is a group of words that includes a subject and a verb. For example:

• The dog barks when the postman arrives.
(This sentence has two clauses. In the first one (shown in bold), the subject is "the dog" and the verb is "barks." In the second one (highlighted), the subject is "the postman" and the verb is "arrives.")

Notice that "The dogs barks" could stand alone as a sentence. This means it is an independent clause. Conversely, "when the postman arrives" could not stand alone as a sentence. This means it is a dependent clause. (This is a key point throughout this lesson.)

Also, every dependent clause functions as one part of speech: an adjective, an adverb, or a noun. (Don't worry. This is explained below.)

An Explanation of "Clause"

Look at this sentence:

• All the cars stop when they see a red flag.

This sentence has two clauses:

(Clause 1) "All the cars stop"

The subject of this clause is "All the cars," and the verb is "stop." We have shown this clause in bold because it is an independent clause. The main clause in any sentence is an independent clause.

(Clause 2) "when they see a red flag"

The subject of this clause is "they," and the verb is "see." In the opening example, this clause is not shown in bold because it is a dependent clause. Also, this clause is functioning like an adverb. Compare the example with the sentence to "All the cars stop immediately." (This proves that "when they see a red flag" is functioning as an adverb.)

Remember that every dependent clause functions as an adjective, an adverb, or a noun. Look at this infographic:

Types of Clause

All clauses are categorized as one of the following:

(1) An Independent Clause

An independent clause (shown in bold throughout this lesson) can stand alone as a complete sentence. For example:

• John eats eggs.
(This independent clause is literally a sentence. We will use this as our main clause in the next three examples.)

(2) A Dependent Clause

A dependent clause functions like an adjective, an adverb, or a noun. This means there are three types of dependent clause. In each of these examples, the dependent clause is highlighted.

(2a) A Relative Clause

Here is an example of a clause functioning as an adjective. This is called a relative clause (or sometimes an adjective clause).

• John eats eggs that his chickens lay.
(Compare this to "John eats free-range eggs." This proves the clause is functioning as an adjective. The subject of the dependent clause is "his chickens," and the verb of the dependent clause is "lay.")

Read more about relative clauses.

(2b) An Adverbial Clause

Here is an example of a clause functioning like an adverb. This is called an adverbial clause.

• John eats eggs when his chickens lay them.
(Compare this to "John eats eggs regularly." This proves the clause is functioning as an adverb.)

Read more about adverbial clauses.

(2c) A Noun Clause

Here is an example of a clause functioning like a noun. This is called a noun clause.

• John eats what his chickens lay.
(Compare this to "John eats eggs." This proves the clause is functioning as a noun. Notice that the noun clause is part of the independent clause, which is why the dependent clause is bold and highlighted.)

Read more about noun clauses.

Clauses vs Phrases

A clause is different to a phrase because a phrase does not contain a subject and a verb. The difference between clauses and phrases is clearer when you see them side by side:

• Anna sings when she wakes up.
(The shaded text is a clause. It has a subject ("she") and a verb ("wakes up").)
• Anna sings in the morning.
(The shaded text is a phrase. There is no subject and no verb.)

Here is another example:

• The ravens lived where the factories are.
(The shaded text is a clause. It has a subject ("the factories") and a verb ("are").)
• The ravens lived in the area of the factories.
(The shaded text is a phrase. There is no subject and no verb.)

Clauses vs Phrases (Interactive Examples)

Here are some interactive examples to help explain the difference between clauses, phrases, and single words. In these examples, the subjects are blue, and the verbs are green.

Video Lesson

Here is a short video summarizing this lesson on clauses. video lesson

Are you a visual learner? Do you prefer video to text? Here is a list of all our grammar videos.

More Examples of Clauses

Here are some more examples of clauses. Remember that the independent clauses are shown in bold and the dependent clauses are highlighted. If some text is neither highlighted nor bold, then it is not a clause.

• During the day, Vlad slept in a coffin.
(The subject of this clause is "Vlad." The verb is "slept." "During the day" is a phrase because there is no verb.)
• When the Moon shone, he lurked in the shadows.
(The subject of the first clause is "the Moon." The verb is "shone." The subject of the second clause is "he." The verb is "lurked.")
• He stalked a pretty milkmaid, who lived in the neighbouring village.
(The subject of the first clause is "He." The verb is "stalked." The subject of the second clause is "who." The verb is "lived.")

Here are three real-life quotations with the clauses explained.

• Even though I made $800 million, I am still grounded. (Boxer Floyd Mayweather)
(The independent clause could stand alone as a sentence, but the dependent clause couldn't.)
• After I die, I'll be forgotten. (Anon)
• A computer once beat me at chess, but it was no match for me at kick boxing. (Comedian Emo Philips)
(It is possible to have a sentence with two independent clauses. This is called a compound sentence.)

The opening words of the dependent clauses above ("even though" and "after") are called subordinating conjunctions. Subordinating conjunctions link a dependent clause to an independent clause.

Using Dependent Clauses in Sentences

Remember that a dependent clause can function as one of three parts of speech: an adjective, an adverb, or a noun.

(1) Using Clauses as Adjectives

• My friend who lives in London looks like Homer Simpson.
(The dependent clause functions like an adjective. It could be replaced with an adjective, e.g., "my London-based friend." Notice that it sits within the independent clause.)
• You should never make fun of something that a person can't change about themselves. (YouTuber Phil Lester)
(This dependent clause could be replaced with an adjective, e.g., "unchangeable.")

(2) Using Clauses as Adverbs

• He lost his double chin after he gave up chocolate.
(The dependent clause functions like an adverb. It could be replaced with an adverb, e.g., "recently.")
• I am not afraid of the pen, the scaffold, or the sword. I will tell the truth wherever I please. (Labour-rights campaigner Mary Harris Jones aka "Mother Jones")
(The first sentence does not have a dependent clause. In the second sentence, the dependent clause could be replaced with an adverb, e.g., "there.")

(3) Using Clauses as Nouns

• She cannot remember what she said last night.
(The dependent clause functions like a noun. It could be replaced with a noun, e.g., "her rant." Notice that the noun clause is part of the independent clause. This is common with noun clauses.)
• Now I know why tigers eat their young. (Mobster Al Capone)
(This dependent clause could be replaced with a noun, e.g., "the reason.")

Why Clauses Are Important

Here are two great reasons to care about clauses. (For the rest of this lesson, we have stopped bolding the independent clauses.)

(1) Understanding when to offset an adjective clause with commas.

The adjective clauses in these two sentences are identical, except one is offset with commas and one isn't. They are both punctuated correctly. So, what's going on?

• A boy who went to my school won the lottery.
• Michael Carroll, who went to my school, won the lottery.

Look at the first example. When a relative clause (also called an adjective clause) is required to identify its noun (here, "boy"), then it is not offset with commas. (Put another way, the subject of the sentence is "A boy who went to my school.")

Look at the second example. When a relative clause is just additional information, then it is offset with commas. (Put another way, the subject of the sentence is "Michael Carroll.") If you'd happily put brackets around the clause or delete it, then it should be offset with commas.

Here are some more examples:

• You went through a phase when you dyed your hair purple.
(There is no comma because the clause is needed to identify the phase. A clause that's necessary for identification is called a restrictive clause.)
• You went through a punk phase, when you dyed your hair purple.
(There is a comma because the phase has already been identified as the punk phase. The clause is just additional information. A clause that's just additional information is called a non-restrictive clause.)
• You went through a mod phase, when you started school, a punk phase when you dyed your hair purple , and a punk phase when you dyed your hair green.
(The first relative clause is just additional information (hence the commas), but the other two are required to identify the punk phases (hence no commas).)

Lots of writers fly by the seat of their pants when it comes to commas, and mistakes with commas are extremely common. Therefore, this is a key point for writers.

Is the Clause Essential or Non-essential?

If you'd happily put your clause in brackets or delete it, then use commas because it must be non-essential.

(2) Understanding when to offset an adverbial clause with commas.

The adverbial clauses in these two sentences are identical, except one is offset with a comma and one isn't. They are both punctuated correctly. So what's going on?

• When the game has finished, the king and pawn go in the same box. (Italian Proverb)
• The king and pawn go in the same box when the game has finished.

When your adverbial clause (or phrase for that matter) is at the front of a sentence (often called a "fronted adverbial"), it is good practice to use a comma afterwards (as in the first sentence above). When it's at the back, the comma tends to be omitted (as in the second sentence).

This "rule" works well with most adverbial clauses (which tend to be adverbs of time, place, or condition). Look at the commas after the fronted adverbials in these examples:

Adverbial Clauses of Time

• When you win, say nothing. When you lose, say less. (NFL coach Paul Brown)
• Say nothing when you win. Say less when you lose.

Adverbial Clauses of Place

• Where there are too many soldiers, there is no peace. Where there are too many lawyers, there is no justice. (Chinese philosopher Lin Yutang)
• There is no peace where there are too many soldiers. There is no justice where there are too many lawyers.

Adverbial Clauses of Condition

• If you think you can, you can. If you think you can't, you're right. (Businesswoman Mary Kay Ash)
• You can if you think you can. You're right if you think you can't.

Key Points

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