A Subordinate Clause adds meaning to a sentence by connecting a dependent clause to the main idea. It can provide information that helps the reader understand a thought more clearly. Unlike independent clauses, which can form complete sentences and stand alone, a subordinate clause needs another clause to make a complete sentence. For example, Because I forgot my keys, the lights were off. The subject and verb are present, but the words still feel unfinished. This combination leaves the reader expecting additional information, showing why these terms describe the same thing: a subordinate clause is also a dependent clause.
A clause usually contains a subject and a verb, while a subordinate clause often begins with a subordinate conjunction or relative pronoun. Common subordinate conjunctions, such as when and if, help express time, condition, cause, contrast, and relationship between ideas. In English, this structure combines ideas within a single sentence instead of producing short, disconnected statements. A useful way to recognize one is to check whether the group of words can express a complete thought by itself. If it cannot, it may be a subordinate structure that needs another clause.
This structural difference becomes especially useful as writers move from beginner writing toward fluent writing. Without these structures, writers may create a sentence fragment, which is one of the common errors associated with incomplete sentences. Writers also need to watch verb tense, particularly the wrong verb tense that can appear after when and if. A practical guide should therefore explain not only what subordinate structures are, but also how they organize ideas and make sentences clearer.
What Is a Subordinate Clause?
A subordinate clause is a group of words that contains a subject and a verb but depends on another clause to form a complete sentence.
It is also called a dependent clause because it cannot normally stand alone as a complete sentence.
For example:
We canceled the picnic because it was raining.
Here, because it was raining is the subordinate clause. It has:
- Subject: it
- Verb: was raining
- Subordinating conjunction: because
However, because it was raining does not express a complete thought by itself. The reader naturally expects more information.
The main clause is:
We canceled the picnic.
That clause can stand alone. Together, the two clauses create a complete and meaningful sentence.
Subordinate Clause Definition in Simple Terms
The easiest way to remember the definition is this:
A subordinate clause has a subject and verb, but it relies on a main clause to complete the meaning.
This dependence separates a subordinate clause from an independent clause.
Compare these examples:
| Clause | Subject | Verb | Complete thought? |
| She finished her homework. | She | finished | Yes |
| Because she finished her homework | she | finished | No |
| The dog barked loudly. | The dog | barked | Yes |
| When the dog barked loudly | the dog | barked | No |
The words because and when change the grammatical relationship. They make the clauses dependent on another idea.
Independent Clause vs. Subordinate Clause
Understanding the difference between an independent clause and a subordinate clause makes sentence analysis much easier.
An independent clause expresses a complete thought and can stand alone as a sentence.
A subordinate clause contains a subject and verb but depends on an independent clause.
For example:
I called Sarah because I needed her help.
The first part can stand alone:
I called Sarah.
The second part cannot normally stand alone:
Because I needed her help.
The word because signals that the second clause explains a reason but does not function as an independent sentence.
Main Differences
| Feature | Independent Clause | Subordinate Clause |
| Complete thought | Yes | Usually no |
| Can stand alone | Yes | No |
| Has a subject | Yes | Yes |
| Has a verb | Yes | Yes |
| Also called | Main clause | Dependent clause |
| Typical role | Main idea | Supporting information |
A useful test is to remove the introductory word and examine the remaining words.
Although she was tired
Without although, we have:
She was tired.
That is a complete clause. Adding although makes it dependent:
Although she was tired, she continued working.
This test works frequently, although the exact grammatical behavior depends on the type of subordinate clause.
How to Identify a Subordinate Clause
Spotting a subordinate clause becomes easier when you follow a few steps.
Look for a Subject and Verb
First, determine whether the group of words contains a subject and a verb.
because the children were playing
Children is the subject. Were playing is the verb phrase.
That means you are dealing with a clause rather than a simple phrase.
Check Whether It Can Stand Alone
Next, ask whether the clause expresses a complete thought.
When the movie ended
The reader immediately wonders what happened when the movie ended.
Compare:
The movie ended.
That sentence stands on its own.
Look for a Subordinating Word
Many subordinate clauses begin with words that signal dependence.
Common examples include:
because, although, if, unless, when, while, before, after, since, until, whenever, wherever, whereas, though, even though, so that, who, which, that, what, whether, and whom.
However, don’t identify a subordinate clause based on the first word alone. You still need to examine the clause’s grammatical function.
Determine Its Function
Finally, ask what job the clause performs.
Does it act like a noun?
Does it describe a noun or pronoun?
Does it provide information about time, reason, condition, contrast, purpose, or another circumstance?
That question often reveals the type of subordinate clause.
The Three Main Types of Subordinate Clauses
English grammar traditionally divides subordinate clauses into three major functional categories:
- Noun clauses
- Adjective clauses
- Adverb clauses
Each type performs a different job.
Noun Clauses
A noun clause is a subordinate clause that performs a function normally associated with a noun.
It can act as a subject, direct object, object of a preposition, or subject complement, depending on the sentence.
Consider:
What she said surprised everyone.
The clause what she said acts as the subject of the sentence.
Now look at:
I know that he is honest.
The clause that he is honest functions as the object of know.
Common Words That Introduce Noun Clauses
Noun clauses can begin with several different words, including:
- that
- what
- who
- whom
- whether
- why
- how
- where
- when
- whoever
- whatever
Examples include:
I don’t know where she went.
Tell me what you need.
We haven’t decided whether we should leave.
Why he left remains unclear.
One important point is that not every clause beginning with these words is automatically a noun clause. Its function within the larger sentence determines its classification.
A Simple Noun Clause Test
Try replacing the clause with a pronoun such as it or something when the context allows it.
I know what she wants.
You could simplify the grammatical structure as:
I know it.
The replacement isn’t always natural in meaning, but it shows that the clause occupies a noun-like position.
Adjective Clauses
An adjective clause, also called a relative clause, modifies a noun or pronoun.
In other words, it gives additional information about someone or something.
For example:
The woman who lives next door is a doctor.
The clause who lives next door describes the woman.
Another example:
I read the book that you recommended.
The clause that you recommended identifies or describes the book.
Common Relative Words
Adjective clauses often begin with:
- who
- whom
- whose
- which
- that
Examples:
The student who won the scholarship thanked her teacher.
The person whom you contacted has replied.
The artist whose work won the prize lives in Chicago.
The car that I bought last year still runs well.
The laptop, which I bought in July, works perfectly.
Restrictive and Nonrestrictive Adjective Clauses
A major distinction involves whether the information is essential.
A restrictive relative clause identifies the noun more specifically.
The students who studied regularly passed the exam.
The clause identifies which students the sentence means.
A nonrestrictive relative clause adds extra information that isn’t essential to identifying the noun.
My brother, who lives in Dallas, is visiting next week.
The commas show that who lives in Dallas provides additional information.
In American English, that generally appears in restrictive relative clauses rather than nonrestrictive ones.
Adverb Clauses
An adverb clause modifies a verb, adjective, adverb, or sometimes the meaning of the entire main clause.
These clauses commonly explain relationships involving:
- Time
- Reason
- Condition
- Contrast
- Purpose
- Place
- Result
- Comparison
For example:
We stayed inside because it was raining.
The subordinate clause explains why we stayed inside.
Adverb Clauses of Time
Time clauses tell you when something happens.
Common subordinating words include:
when, whenever, while, before, after, until, once, since, and as soon as.
Examples:
Call me when you arrive.
Before she left, she locked the door.
We waited until the store opened.
Adverb Clauses of Reason
Reason clauses explain why something happens.
Common words include:
because, since, and as.
Examples:
We went home because it was getting late.
Since the roads were icy, school closed early.
Adverb Clauses of Condition
Condition clauses describe circumstances that must exist for something else to happen.
Common words include:
if, unless, provided that, as long as, and even if.
Examples:
If you finish early, you can leave.
You won’t succeed unless you practice.
We’ll go hiking as long as the weather stays clear.
Adverb Clauses of Contrast
Contrast clauses show an unexpected difference between two ideas.
Common expressions include:
although, though, even though, whereas, and while.
Examples:
Although the task was difficult, she completed it.
He went for a walk even though it was cold.
Adverb Clauses of Purpose
Purpose clauses explain why someone takes an action.
Common expressions include:
so that and in order that.
Example:
She spoke quietly so that the baby wouldn’t wake up.
The subordinate clause explains the purpose behind speaking quietly.
Common Subordinating Conjunctions and Their Functions
The following table provides a practical reference for common subordinate clause markers.
| Relationship | Common subordinating words | Example |
| Time | when, before, after, while, until | Call me when you arrive. |
| Reason | because, since, as | We left because it was late. |
| Condition | if, unless, provided that | I’ll help if you ask. |
| Contrast | although, though, even though | Although it rained, we went outside. |
| Purpose | so that, in order that | He whispered so that nobody would hear. |
| Place | where, wherever | Sit wherever you like. |
| Comparison | than, as | She runs faster than I do. |
These words provide clues, but the surrounding sentence still determines the exact grammatical role.
Subordinate Clause Sentence Patterns
Subordinate clauses can appear before or after the independent clause.
Subordinate Clause First
Because the traffic was heavy, we arrived late.
The introductory subordinate clause comes first. A comma separates it from the main clause.
Main Clause First
We arrived late because the traffic was heavy.
Here, the subordinate clause follows the main clause. A comma is generally unnecessary when the clause closely connects to the main idea.
Compare the two patterns:
| Pattern | Example |
| Subordinate + comma + main | Although she was tired, she kept working. |
| Main + subordinate | She kept working although she was tired. |
Changing the position can also change the emphasis.
When the subordinate clause comes first, the writer often foregrounds the background circumstance.
Subordinate Clauses in Complex Sentences
A complex sentence contains at least one independent clause and at least one subordinate clause.
For example:
I stayed home because I wasn’t feeling well.
The independent clause is:
I stayed home.
The subordinate clause is:
because I wasn’t feeling well.
Together, they create a complex sentence.
Complex sentences aren’t automatically better than simple sentences. The point is not to make every sentence longer. Instead, subordinate clauses help show how ideas relate to each other.
Compare:
The alarm rang. I woke up.
With:
I woke up when the alarm rang.
The second version makes the time relationship explicit.
Multiple Subordinate Clauses in One Sentence
A sentence can contain more than one subordinate clause.
For example:
When the meeting ended, we spoke to the manager because we had questions.
Here, the sentence contains two subordinate clauses:
- When the meeting ended — adverb clause of time
- because we had questions — adverb clause of reason
Another sentence can combine different types:
I spoke to the employee who handled my account because I needed to know what had happened.
This structure contains an adjective clause and a noun clause within a larger complex sentence.
Multiple subordinate clauses can be useful. However, piling them into every sentence can make prose difficult to follow. Good writing balances complexity with clarity.
Subordinate Clause vs. Phrase
A clause contains a subject-verb relationship. A phrase does not function as a complete clause.
Compare:
because of the rain
and:
because it rained
The first is a prepositional phrase.
The second contains a subject (it) and a verb (rained), making it a clause.
| Expression | Type |
| because of the rain | Phrase |
| because it rained | Subordinate clause |
| after the meeting | Phrase |
| after the meeting ended | Subordinate clause |
| despite the delay | Phrase |
| although we were delayed | Subordinate clause |
This distinction matters because writers sometimes mistake a prepositional phrase for a subordinate clause.
Subordinate Clause vs. Coordinate Clause
Coordination and subordination create different relationships between ideas.
A coordinating conjunction joins elements of relatively equal grammatical status.
I wanted to go, but I was tired.
Both clauses can stand independently:
I wanted to go.
I was tired.
Subordination works differently:
I didn’t go because I was tired.
The clause because I was tired depends on the main clause.
Coordination vs. Subordination
| Coordination | Subordination |
| Joins equal clauses | Connects a dependent clause to a main clause |
| Uses coordinating conjunctions | Often uses subordinating conjunctions |
| Both clauses can usually stand alone | The subordinate clause cannot normally stand alone |
| Example: I called, but she didn’t answer. | I called because I needed help. |
Understanding this distinction helps you build sentences deliberately rather than simply adding conjunctions wherever they seem to fit.
Punctuation Rules for Subordinate Clauses
Punctuation depends partly on where the subordinate clause appears and what type of clause it is.
Introductory Adverb Clauses
When an adverb clause comes before the independent clause, a comma usually separates the two.
After the rain stopped, the children went outside.
Although he was nervous, he gave the presentation.
Adverb Clauses at the End
When the subordinate adverb clause follows the main clause, a comma is often unnecessary.
The children went outside after the rain stopped.
He gave the presentation although he was nervous.
However, punctuation can vary when the writer wants to emphasize a strong interruption or unusual construction.
Nonrestrictive Relative Clauses
Nonessential relative clauses normally require commas.
My car, which I bought last year, needs new tires.
The clause adds information about the car without identifying which car the writer means.
A restrictive clause doesn’t use commas:
The car that I bought last year needs new tires.
Here, the clause helps identify the specific car.
Common Subordinate Clause Errors
Even experienced writers can mishandle dependent clauses. A few errors appear especially often.
Sentence Fragments
A subordinate clause cannot normally function as a sentence by itself.
Incorrect:
Because I was tired.
Correct:
I went to bed early because I was tired.
The first version leaves the reader waiting for the main idea.
Missing Main Clauses
Another common mistake occurs when a writer begins with a dependent clause and forgets to finish the sentence.
Incorrect:
Although the weather was improving.
Correct:
Although the weather was improving, we stayed indoors.
The dependent clause needs an independent clause to complete the thought.
Incorrect Comma Placement
Writers sometimes place a comma between the subject and its verb simply because a subordinate clause appears nearby.
Incorrect:
The student who won the contest, received a scholarship.
Correct:
The student who won the contest received a scholarship.
The restrictive adjective clause doesn’t require commas.
Confusing Because With Because Of
These expressions have different grammatical structures.
Because introduces a clause:
We stayed home because it was raining.
Because of introduces a noun phrase:
We stayed home because of the rain.
This is a small distinction, but it can prevent many sentence-structure errors.
Overloading a Sentence
A sentence can contain too many subordinate clauses.
For example:
Although the manager, who had recently joined the company, explained that the project, which had already experienced several delays, would probably finish soon because the team had found a solution that seemed promising, the clients remained concerned.
The grammar may be workable, but the sentence demands considerable concentration.
Breaking it up can improve readability:
Although the manager said the project would probably finish soon, the clients remained concerned. The project had already experienced several delays.
Complex grammar should clarify relationships, not bury the main point.
How Subordinate Clauses Improve Writing
Used well, subordinate clauses give your writing precision.
They can explain why something happened:
She left early because she had an appointment.
They can establish when something happened:
We started dinner after everyone arrived.
They can create a condition:
If you need assistance, call the front desk.
They can introduce contrast:
Although the task looked easy, it required careful planning.
They can describe a person or thing:
The employee who answered the phone was helpful.
They can identify information:
I understand what you mean.
Instead of merely placing facts next to one another, subordinate clauses show the logical connection between them.
Subordinate Clauses in Everyday English
You don’t need formal academic writing to use dependent clauses. They appear constantly in ordinary conversation.
Consider these natural sentences:
I’ll call you when I get home.
Let me know if you need anything.
We can leave after everyone is ready.
The restaurant that you recommended was excellent.
I don’t know why she left.
Even though I was tired, I finished the assignment.
These sentences sound natural because subordinate clauses help speakers package related ideas efficiently.
In conversation, people also sometimes use dependent clauses as fragments:
“Because I was tired.”
That can be acceptable in informal dialogue when the missing main clause is obvious from the context. Formal writing generally requires a complete sentence.
How to Use Subordinate Clauses Effectively
The best subordinate clauses aren’t added simply to make sentences longer. Each one should perform a clear job.
Start With the Relationship
Before choosing a subordinating conjunction, determine what relationship you need.
Do you want to express:
- Time? Use when, before, after, or until.
- Reason? Use because, since, or as.
- Condition? Use if or unless.
- Contrast? Use although or even though.
- Purpose? Use so that.
- Description? Consider a relative clause.
Keep the Main Idea Visible
A reader shouldn’t have to search through several clauses to find the main point.
Instead of:
Because the weather was changing and the roads were becoming difficult to navigate, we decided that since several members of the group had already expressed concerns, it would probably be better to postpone the trip.
Try:
Because the weather was worsening, we decided to postpone the trip.
The second sentence delivers the main idea quickly.
Match the Conjunction to the Meaning
Don’t choose although when you mean because.
Compare:
Although it was raining, we went outside.
This expresses contrast.
Because it was raining, we stayed inside.
This expresses reason.
The conjunction isn’t decorative. It tells the reader how the ideas relate.
Subordinate Clause Examples With Explanations
| Complete sentence | Subordinate clause | Type | Function |
| We left because it was late. | because it was late | Adverb | Gives a reason |
| When the bell rang, students left. | When the bell rang | Adverb | Gives a time |
| If you need help, call me. | If you need help | Adverb | Gives a condition |
| The woman who called you is here. | who called you | Adjective | Describes the woman |
| I know what you mean. | what you mean | Noun | Acts as the object of know |
| Although he was tired, he continued. | Although he was tired | Adverb | Shows contrast |
| The book that you lent me was useful. | that you lent me | Adjective | Identifies the book |
| She explained why she was late. | why she was late | Noun | Acts as the object of explained |
This table demonstrates an important principle: the same general idea of dependence can appear in very different grammatical roles.
A Practical Subordinate Clause Checklist
When you’re unsure whether a group of words is a subordinate clause, ask these questions:
- Does it contain a subject?
- Does it contain a verb?
- Does it express a complete thought by itself?
- Does a subordinating conjunction or relative word introduce it?
- Does it depend on another clause?
- Does it act like a noun, adjective, or adverb?
- Does the punctuation match its position and function?
If the clause contains a subject and verb but cannot stand independently, you probably have a subordinate clause.
Quick Practice: Find the Subordinate Clause
Try identifying the dependent clause in each sentence.
Because the store was closed, we went somewhere else.
I smiled when I saw my old friend.
The laptop that you recommended works well.
I don’t understand why he changed his mind.
Although the exam was difficult, most students finished on time.
The answers are:
- Because the store was closed — adverb clause
- when I saw my old friend — adverb clause
- that you recommended — adjective clause
- why he changed his mind — noun clause
- Although the exam was difficult — adverb clause
Practice like this helps you move beyond memorizing definitions. Eventually, you’ll recognize subordinate clauses by how they function inside the sentence.
Why Subordinate Clauses Matter for Fluent English
Fluent English isn’t simply about knowing more vocabulary. It’s also about understanding how ideas fit together.
A sentence such as:
I was hungry. I ordered food.
is perfectly grammatical, but it leaves the relationship unstated.
A subordinate clause can make the connection explicit:
Because I was hungry, I ordered food.
Likewise:
She studied hard because she wanted to improve her grade.
The subordinate clause tells the reader exactly why the action occurred.
That ability to show cause, time, condition, contrast, purpose, and description is one reason subordinate clauses play such an important role in sophisticated English sentence construction.
Conclusion
A subordinate clause adds useful detail to a sentence but cannot normally stand alone as a complete sentence. It depends on an independent clause to express a complete thought. Recognizing words such as when, if, and because can help you identify these clauses and understand their purpose. Once you understand how they show cause, condition, time, contrast, and relationship, you can build clearer and more fluent English sentences.
FAQs
What is a subordinate clause?
A subordinate clause is a group of words containing a subject and verb that does not express a complete thought by itself. It needs an independent clause to complete the sentence.
Is a subordinate clause the same as a dependent clause?
Yes. Subordinate clause and dependent clause are two terms for the same grammatical structure.
Can a subordinate clause stand alone?
No. A subordinate clause cannot normally stand alone as a complete sentence because it leaves the reader expecting more information.
What does a subordinate clause begin with?
A subordinate clause commonly begins with a subordinating conjunction, such as because, when, if, although, or while. It can also begin with a relative pronoun in some structures.
What is an example of a subordinate clause?
“Because I forgot my keys” is a subordinate clause. It has a subject and verb, but it needs a main clause to complete the thought.
Why are subordinate clauses important?
They allow you to combine related ideas in one sentence and show relationships such as cause, condition, time, and contrast.
