Subordinate Clauses

clause definitions | noun clause | adjective clause | adverb clause

A clause is nothing more than a subject-verb structure. If the clause expresses a complete thought and is written by itself, we call it a sentence. If the clause expresses a complete thought, but is written as part of a compound sentence, a complex sentence, or a compound-complex sentence, we call it an independent clause or a main clause.

But if the clause does not express a complete thought on its own, we call it a subordinate clause. A subordinate clause is always a part of a complex sentence or a compound-complex sentence and cannot be written alone without creating a fragment.

A complex sentence is the merging of two simple sentences, making one of the two sentences a main or independent clause, and turning the other sentence into a subordinate clause that will be used as part of the first sentence. This is what it means to "subordinate" a clause. For example, we can combine these two sentences into one complex sentence that uses a noun clause:

We can combine these two simple sentences into one complex sentence, by turning one of them into part of the other.

We can turn the second sentence into a noun clause and use it as the direct object of the first sentence, replacing the indefinite pronoun something:


James said (that) this year's team is the best in our school's history.


The word that or some other word to begin the subordinatae clause may be required when joining some simple sentences into a complex sentence. The point of subordinate clauses is this:

The subordinate clause began its life as a simple sentence, but now functions as part of another simple sentence. When we form a complex sentence, we subordinate one simple sentence to function as a part of another simple sentence. A subordinate clause can be used as an noun, as an adjective, or as an adverb.

♦ Noun clause

A noun clause is a subject-verb structure that is used as a single noun; that's right, the entire group of words forming the subject-verb structure (including its modifiers and complements) is used as a single noun.

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♦ Adjective clause

An adjective clauses is a subject-verb structure (including complements and modifiers) that is used as a single adjective.

A relative pronoun introduces or begins an adjective clause. The relative pronouns are who, whoever, whom, whomever, whose, which, and that. Because adjective clauses begin with a relative pronoun, such clauses are sometimes called relative clauses.

Who, whoever, whom, whomever, and whose refer to people.

Which refers to animals and objects.

That refers to people, animals, or things.

Let's form a complex sentence that uses an adjective clause. Like all complex sentences, we start with two simple sentences. In the case of adjective clause, a word in one sentence must refer to a noun in the other sentence. For instance,

The pronoun it in the second sentence clearly refers to the noun movie in the first sentence. This suggests that we can combine the two simple sentences into one complex sentence using an adjective clause.

Follow these steps to create a complex sentence that uses an adjective clause:

  1. Find a noun or pronoun in one sentence that refers to a noun in the other sentence. (We have already done this step.)
  2. Replace the pronoun with the correct relative pronoun, keeping case in mind. The relative pronoun is chosen according to its function and case in the original simple sentence from which it comes. Here, it will be replaced with which or that, making the second sentence read I enjoyed which very much.
  3. Bring the relative pronoun to the front of the sentence, thereby forming the adjective clause which I enjoyed very much.
  4. Insert the newly formed adjective clause immediately behind the noun or pronoun in the first sentence, in this case movie, to form the completed complex sentence I saw a movie which I enjoyed very much.
  5. Deternine whether the adjective clause is restrictive or non-restrictive, then punctuate according to the rules given above. Note that sometimes the adjective clause can be correctly written as a restrictive or as a non-restrictive clause, depending on the writer's intent. Here, I will make the adjective clause restrictive and use no commas.

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♦ Adverb clause

An adverb clause is a subject-verb structure (including complements and modifiers) that is used as a single adverb.

A subordinating conjunction introduces or begins an adverb clause. There are very many subordinating conjunctions, many of which can also be used as prepositions.

Let's form a complex sentence that uses an adverb clause. Like all complex sentences, we start with two simple sentences.

Since both of these events cannot happen at the same time, we must decide which one we will do first. All of the following are correct combinations of these two simple sentences. We know we are forming an adverb clause because the simple sentence converted to the subordinate clause answers the question when about the action of the other simple sentence.

Notice how moveable adverb clauses are. All of the following say the same thing, but the adverb clause is clearly in different positions.

(Note the use of commas when using an introductory adverb clause or an interrupting adverb clause.)

Where does a 500 pound canary sleep?
Anywhere he wants to!
Adverb clauses are like that.

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Check Your Understanding:

Indicate the type and function of the subordinate clause in each of the following sentences:

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