Dependent Clauses
Learn why a dependent clause cannot stand alone, what signals that dependency, and how its position changes the punctuation of the sentence it belongs to.
Needing more to be complete
A dependent clause leaves the reader waiting for the rest.
A dependent clause contains a subject and a verb, just like an independent clause, but it does not express a complete thought. It depends on being attached to an independent clause to make sense.
In because she was tired, the subject she and the verb was are both present, but the word because leaves the reader expecting more. Attached to an independent clause, as in She left early because she was tired., the sentence becomes complete.
A word at the start of the clause, such as because, who, or what, usually signals that a clause is dependent.
Before you begin
Dependent clauses are one of five clause types.
This lesson focuses on dependent clauses specifically. Clauses as a whole include four other types, each covered in its own lesson.
If you would like an overview of how clauses work in general, begin with the Clauses page.
The central idea
A dependent clause becomes complete once it is attached.
Compare the dependent clause alone with the same clause attached to an independent clause.
01
Alone
Because she was tired
02
Attached
She left early because she was tired.
The useful question is: does this leave the reader expecting more?
Because she was tired raises the question then what? Only once it is attached to an independent clause is that question answered.
What signals dependency
An opening word usually marks a clause as dependent.
A subordinating conjunction
Although it was raining, they went for a walk.
Words such as because, although, if, when and while attach a clause to a main idea.
A relative pronoun
The man who called left a message.
Words such as who, which and that attach a clause describing a noun.
A question word used to open a noun clause
What she said surprised everyone.
Words such as what, whether and how can introduce a clause that functions as a noun.
Going further with dependent clauses
This lesson introduces dependent clauses in general.
A dependent clause always does one of three jobs in a sentence: describing a noun, acting as a noun, or acting as an adverb. Each job is covered in its own lesson.
A closer look at each job
Relative Clauses, Noun Clauses and Adverb Clauses each explore one of these jobs in greater depth.
Position and punctuation
Where the dependent clause sits changes whether a comma is needed.
Dependent clause first: use a comma
Because it was raining, they stayed inside.
Dependent clause last: no comma is usually needed
They stayed inside because it was raining.
A useful decision guide
Ask what signals the clause is dependent, and where it sits.
01
Does the clause open with a subordinating word?
Words such as because, although, who or what usually signal dependency.
02
Is it attached to an independent clause?
A dependent clause needs one to form a complete sentence.
03
Does the dependent clause come first, or last?
A comma follows it when it comes first; usually none is needed when it comes last.
04
What job is the clause doing?
Check whether it describes a noun, acts as a noun, or acts as an adverb.
Common mistakes
A dependent clause needs an independent clause, and the right comma.
A dependent clause cannot stand alone as a sentence.
Not: Because it was raining.
Correct: Because it was raining, they stayed inside.
Punctuating a dependent clause as its own sentence creates a fragment.
A comma is needed when the dependent clause comes first.
Not: Because it was raining they stayed inside.
Correct: Because it was raining, they stayed inside.
A comma is usually not needed when the dependent clause comes last.
Not: They stayed inside, because it was raining.
Correct: They stayed inside because it was raining.
Check your understanding
Is each group of words a dependent clause?
Choose the correct answer for each example.
When the meeting ends
✅ Exactly! When leaves the reader expecting more information.
❎ Not quite. Does this make complete sense as a stand-alone sentence?
Does this leave you wondering “then what?”
The meeting ends at noon.
✅ Exactly! This clause makes complete sense on its own, with no subordinating word attached.
❎ Not quite. Is there a word here that leaves the sentence needing more?
Could this stand alone as a complete sentence?
that she left on the table
✅ Exactly! That signals this clause is describing something already mentioned.
❎ Not quite. Notice the word this clause opens with.
What word opens this clause?
Choose the best explanation
Select the sentence that explains the mistake correctly.
Why is “Because it was raining.” not a complete sentence?
✅ Exactly! The clause has both a subject and a verb, but “because” makes it dependent on another clause.
❎ Not quite. Look closely for the subject, “it”, and the verb, “was raining”.
Why does “They stayed inside, because it was raining.” need to be corrected?
✅ Exactly! The comma is only needed when the dependent clause opens the sentence.
❎ Not quite. Compare this to the version where the dependent clause comes first.
Try it another way
Complete each sentence.
Add a comma where it is needed, or leave the blank empty if none is needed.
✅ Exactly! A comma follows a dependent clause that opens the sentence.
❎ Not quite. The dependent clause comes first here.
✅ Exactly! No comma is usually needed when the dependent clause comes last.
❎ Not quite. Where does the dependent clause sit in this sentence?
Quick review
A dependent clause needs an independent clause to be complete.
A dependent clause has a subject and a verb, but does not express a complete thought on its own.
A subordinating conjunction, relative pronoun, or question word usually opens a dependent clause.
A dependent clause plays one of three jobs: describing a noun, acting as a noun, or acting as an adverb.
A comma follows a dependent clause that opens the sentence; usually none is needed when it comes last.
Remember
If a clause leaves you expecting more, it is dependent.
Attach it to an independent clause to complete the sentence, and add a comma only when the dependent clause comes first.