Grammar Made Easy


Clauses: the Essential Building-Blocks




A clause is a group of related words containing a subject and a verb A clause can be usefully distinguished from a phrase, which is a group of related words that does not contain a subject-verb relationship, such as "in the morning" or "running down the street" or "having grown used to this harassment." A review of the different kinds of phrases might be helpful.

Words We Use to Talk about Clauses

Learning the various terms used to define and classify clauses can be a vocabulary lesson in itself. This digital handout categorizes clauses into independent and dependent clauses. This simply means that some clauses can stand by themselves, as separate sentences, and some can't. Another term for dependent clause is subordinate clause: this means that the clause is subordinate to another element (the independent clause) and depends on that other element for its meaning. The subordinate clause is created by a subordinating conjunction or dependent word.

An independent clause, "She is older than her brother" (which could be its own sentence), can be turned into a dependent or subordinate clause when the same group of words begins with a dependent word (or a subordinating conjunction in this case): "Because she is older than her brother, she tells him what to do."

Clauses are also classified as restrictive and nonrestrictive clauses. (The words essential and nonessential are sometimes used and mean the same thing as restrictive and nonrestrictive, respectively. British grammarians will make this same distinction by referring to clauses with the terms defining and non-defining.) A nonrestrictive clause is not essential to the meaning of the sentence; it can be removed from the sentence without changing its basic meaning. Nonrestrictive clauses are often set apart from the rest of the sentence by a comma or a pair of commas (if it's in the middle of a sentence).

  • Professor Villa, who used to be a secretary for the President, can type 132 words a minute.

Review the Notorious Confusables section on the difference between That and Which for additional clarification on the distinction between restrictive and nonrestrictive.

Relative clauses are dependent clauses introduced by a Relative Pronoun (that, which, whichever, who, whoever, whom, whomever, whose, and of which). Relative clauses can be either restrictive or nonrestrictive. Review the section on Comma Usage for additional help in determining whether relative clauses are restrictive or nonrestrictive (parenthetical or not) and whether commas should be used to set them off from the rest of the sentence. In a relative clause, the relative pronoun is the subject of the verb (remember that all clauses contain a subject-verb relationship) and refers to (relates to) something preceding the clause.

  • Giuseppe said that the plantar wart, which had been bothering him for years, had to be removed.

1. See unit on comma usage

(In this sentence, the clause in this color is a restrictive [essential] clause [a noun clause — see below] and will not be set off by a comma; the underlined relative clause [modifying "wart"] is nonrestrictive [nonessential — it can be removed from the sentence without changing the meaning of the sentence] and is set off by commas.)

Some relative clauses will refer to more than a single word in the preceding text; they can modify an entire clause or even a series of clauses.

  • Charlie didn't get the job in administration, which really surprised his friends.
    Charlie didn't get the job in administration, and he didn't even apply for the Dean's position, which really surprised his friends.

A relative clause that refers to or modifies entire clauses in this manner is called a sentential clause. Sometimes the "which" of a sentential clause will get tucked into the clause as the determiner of a noun:

  • Charlie might very well take a job as headmaster, in which case the school might as well close down.

Elliptical Clauses:

Finally, everybody's favorite clause is the Santa Clause, which needs no further definition:

Independent Clauses

Independent Clauses could stand by themselves as discrete sentences, except that when they do stand by themselves, separated from other clauses, they're normally referred to simply as sentences, not clauses. The ability to recognize a clause and to know when a clause is capable of acting as an independent unit is essential to correct writing and is especially helpful in avoiding sentence fragments and run-on sentences..

Needless to say, it is important to learn how to combine independent clauses into larger units of thought. In the following sentence, for example,

  • Bob didn't mean to do it, but he did it anyway.

we have two independent clauses — "Bob didn't mean to do it" and "he did it anyway" — connected by a comma and a coordinating conjunction ("but"). If the word "but" is missing from this sentence, the sentence would be called a comma splice: two independent clauses would be incorrectly connected, smooshed together, with only a comma between them. Furthermore, a long series of clauses of similar structure and length begins to feel monotonous, leading to what is called "Dick and Jane" or primer language (after the kind of prose that we find in first grade textbooks or "primers").

Clauses are combined in three different ways: coordination, subordination, and by means of a semicolon. Coordination involves joining independent clauses with one of the coordinating conjunctions: and, but, or, nor, for, yet, and sometimes* so. Clauses thus connected are usually nicely balanced in length and import.

  • Ramonita thought about joining the church choir, but she never talked to her friends about it.

Subordination involves turning one of the clauses into a subordinate element (one that cannot stand on its own) through the use of a Subordinating Conjunction (sometimes called a dependent word) or a Relative Pronoun. When the clause begins with a subordinating word, it is no longer an independent clause; it is called a dependent or subordinate clause because it depends on something else (the independent clause) for its meaning. There are other ways of combining ideas — by turning independent clauses into various kinds of modifying phrases.

  • Although Ramonita often thought about joining the choir, she never talked to her friends about it.
  • Ramonita never talked to her friends about joining the choir, because she was afraid they would make fun of her.
  • Yasmin is Ramonita's sister. Yasmin told Ramonita to join the choir no matter what her friends said.
    Joining these with the use of a relative clause:
    Yasmin, [who is] Ramonita's sister, told Ramonita to join the choir. . . .

Semicolons can connect two independent clauses with or without the help of a conjunctive adverb (transitional expression). Semicolons should be used sparingly and only when the two independent clauses involved are closely related and nicely balanced in terms of length and import.

  • Ramonita has such a beautiful voice; many couples have asked her to sing at their wedding.
  • Ramonita's voice has a clear, angelic quality; furthermore, she clearly enjoys using it.

Identifying Independent and Dependent Clauses

When you want to use commas and semicolons in sentences and when you are concerned about whether a sentence is or is not a fragment, a good way to start is to be able to recognize dependent and independent clauses. The definitions offered here will help you with this.

Independent Clause

An independent clause is a group of words that contains a subject and verb and expresses a complete thought. An independent clause is a sentence.

Jim studied in the Sweet Shop for his chemistry quiz.

Dependent Clause

A dependent clause is a group of words that contains a subject and verb but does not express a complete thought. A dependent clause cannot be a sentence. Often a dependent clause is marked by a dependent marker word.

When Jim studied in the Sweet Shop for his chemistry quiz . . . (What happened when he studied? The thought is incomplete.)


Dependent Marker Word

A dependent marker word is a word added to the beginning of an independent clause that makes it into a dependent clause.

When Jim studied in the Sweet Shop for his chemistry quiz, it was very noisy.

Some common dependent markers are: after, although, as, as if, because, before, even if, even though, if, in order to, since, though, unless, until, whatever, when, whenever, whether, and while.


Connecting dependent and independent clauses

There are two types of words that can be used as connectors at the beginning of an independent clause: coordinating conjunctions and independent marker words.

1. Coordinating Conjunction

The seven coordinating conjunctions used as connecting words at the beginning of an independent clause are and, but, for, or, nor, so, and yet. When the second independent clause in a sentence begins with a coordinating conjunction, a comma is needed before the coordinating conjunction:

Jim studied in the Sweet Shop for his chemistry quiz, but it was hard to concentrate because of the noise.

2. Independent Marker Word

An independent marker word is a connecting word used at the beginning of an independent clause. These words can always begin a sentence that can stand alone. When the second independent clause in a sentence has an independent marker word, a semicolon is needed before the independent marker word.

Jim studied in the Sweet Shop for his chemistry quiz; however, it was hard to concentrate because of the noise.

Some common independent markers are: also, consequently, furthermore, however, moreover, nevertheless, and therefore.

Some Common Errors to Avoid

Comma Splices

A comma splice1 is the use of a comma between two independent clauses. You can usually fix the error by changing the comma to a period and therefore making the two clauses into two separate sentences, by changing the comma to a semicolon, or by making one clause dependent by inserting a dependent marker word in front of it.

Incorrect: I like this class, it is very interesting.

  • Correct: I like this class. It is very interesting.
  • (or) I like this class; it is very interesting.
  • (or) I like this class, and it is very interesting.
  • (or) I like this class because it is very interesting.
  • (or) Because it is very interesting, I like this class.

Fused Sentences

Fused sentences happen when there are two independent clauses not separated by any form of punctuation. This error is also known as a run-on sentence. The error can sometimes be corrected by adding a period, semicolon, or colon to separate the two sentences.

Incorrect: My professor is intelligent I've learned a lot from her.

  • Correct: My professor is intelligent. I've learned a lot from her.
  • (or) My professor is intelligent; I've learned a lot from her.
  • (or) My professor is intelligent, and I've learned a lot from her.
  • 1. See unit on comma usage

    (or) My professor is intelligent; moreover, I've learned a lot from her.

Sentence Fragments

Sentence fragments happen by treating a dependent clause or other incomplete thought as a complete sentence. You can usually fix this error by combining it with another sentence to make a complete thought or by removing the dependent marker.

Incorrect: Because I forgot the exam was today.

  • Correct: Because I forgot the exam was today, I didn't study.
  • (or) I forgot the exam was today.


Main clauses and dependent adverb clauses

The following clauses are independent. They are complete sentences, or can be main clauses in longer sentences.

I went to the skating rink yesterday.

My paper was too long.

Go home. (The subject is "you.")

These clauses are dependent, or subordinate. They cannot stand alone as complete sentences.

  • After I went to the skating rink yesterday,...
  • Because my paper was too long,...
  • ...if you go home.

A dependent clause must be paired with at least one independent clause to create a complete sentence.

After I went to the skating rink yesterday, I ran into an old friend in the parking lot.

You'll miss the grand finale if you go home.

If a dependent clause appears before the main clause, there is a comma after the dependent clause. However, if the main clause is first, no comma is needed between them.

Unless I hear from them soon, I'll assume I didn't get the job.

I'll assume I didn't get the job unless I hear from them soon.


Words that signal a dependent clause

These are words which writers commonly use at the beginning of a dependent clause.

  • Time: after, before, until, when, while, as.
  • Cause: because, since, so that.
  • Condition: unless, although, if, as if, whether (...or not).


Other types of subordinate clauses

Besides the adverb clauses described above, there are two other types of subordinate clauses, adjective clauses and noun clauses. The subordinate clauses in the sentences below are underlined.

People who live in glass houses shouldn't throw stones. (contains a relative clause which modifies "people")


That is the school where I attended eleventh and twelfth grades. (contains an adjective clause which modifies "school")


What you don't know can hurt you. (contains a noun clause as the subject)

Remember that although a subordinate clause contains a verb, it can not be the main clause. The following sentence is incomplete because it lacks a main clause.

People who own exotic pets. (What about those people? The writer needs to complete the thought.)

Clause types

Main clauses

A main clause is complete on its own. It may be a complete sentence written with a capital letter and full stop (or ?!):

Alice saw a rabbit.

Anna is eating her favourite supper.

Finally, we arrived.

Simple sentences consist of just one main clause:

Hannah is eating her favourite supper.

Finally, we arrived.

Compound sentences consist of two or more main clauses – clauses of equal weight, joined together by and, or, but, or so.

I’ve lost my school bag but the keys are here so I’m not locked out.

It’s late, so she’s not going.

I like reading and I love Hemingway.

Compound sentences contain one or more subordinate clauses.

Subordinate clauses

A subordinate clause is part of a larger clause.

He burns easily if he doesn’t use sun cream.

Where is the cup of tea that you promised to make?

Everything she buys is really expensive.

The class I taught last year all did quite well.

Because the subordinate clause is part of the larger clause, the remainder of this clause is not itself a complete clause; so in the first example above the main clause is the entire sentence, not He burns easily.

Using subordinate clauses allows writers to vary pace and rhythm and to indicate the relative importance of different ideas.

Subordination signals

You can usually recognise subordinate clauses easily because they are signalled:

We ate early, being excessively hungry.

To be ready in time, he did without supper.

Having eaten early, we watched the news.

We helped unpack the tent.

They sat there until it started to rain.

He’s the one who started it.

After he arrived things started to happen.

They will walk out unless we give in to them.

However, some subordinate clauses have no signal at all, because the subordinating word - which is always that - is omitted. They are harder to recognise, but can nearly always be identified by replacing the missing that:

I know you are hiding something. (... know that you are ...)

Who says I am a coward? (... says that I am ...)

That man she likes is very tall. (... man that she likes ...)

The book I’m reading won a prize. (... book that I'm reading ...)

This is a common feature of writing at KS3, and pupils need to understand and be able to handle it.

Finite and non-finite clauses

  • Finite clauses have a finite verb as their head.

I know everyone sent their friends birthday cards this year.

  • Non-finite clauses have a non-finite verb (i.e. an infinitive or a participle) as their head.

Everyone promised to send their friends birthday cards this year.

This important difference is always signalled by the first verb in the verb-chain:

I know everyone has sent their friends birthday cards this year.

Everyone hopes to have finished their projects by the end of the week.

Having already finished their projects, they can have a rest.

This difference also affects the ways in which these clauses can be used:

  • Finite clauses may generally be used as complete sentences (once any subordinating words have been removed):

Everyone sent their friends birthday cards this year.

  • Non-finite clauses are always part of a larger clause:

They have made plans to send their friends birthday cards this year.

This is because the use of a non-finite verb such as to send is one of the main signals that a clause is a subordinate clause.

This difference may also affect the meaning of sentences, often in a subtle way. For example, compare:

  • I remembered that I was responsible. (finite)
  • I remembered to do it. (non-finite)
  • I saw that you did it. (finite)
  • I saw you do it. (non-finite)

These highlighted clauses are non-finite:

We really enjoy sailing our dinghy.

Spurred on by the crowd, they won the match.

He struggled to read the small type.

Changing the tense of the sentence doesn’t change the non-finite clause:

  • We enjoyed sailing our dinghy.
  • We will enjoy sailing our dinghy.
  • He struggles to read the small type.
  • He will struggle to read the small type.
  • Spurred on by the crowd, they won the match.
  • Spurred on by the crowd, they are winning the match.

Noun clauses

Noun clauses, like nouns, pronouns and noun phrases, can act as:

  • the object of a verb:

I know that Mary bought the dog.

  • the subject of a verb:

Why she bought it is a great mystery to us all.

  • the object of a preposition:

Don't judge her by what she buys.

  • a complement

She seems to be pleased with it.

If a clause fulfils the role of a noun in a sentence, it is a noun clause.

At Key Stage 3, pupils should be developing the use of expressions like these, where a noun phrase is followed by a noun clause:

We discussed the idea that she had bought a cat.

We discussed the fact that she had bought a cat.

We discussed the possibility that she had bought a cat.

This structure is a useful tool to help thinking skills because it involves important distinctions about the logical status of information - e.g. as facts, beliefs, suggestions, theories, and ideas.

Relative clauses

Relative clauses are adjectival because, like adjectives, they modify a nouns; but unlike adjectives, they come after the modified noun:

Sam is the one who usually sits here.

The shop where I work is closing.

This computer, which I usually use, is faster.

Relative clauses usually start with a relative pronoun:

that, who, which, whom, whose

or a relative adverb:

when, where

Relative pronouns and relative adverbs act as subordinating words – they signal a subordinate clause.

Using relative clauses allows KS3 writers to progress from co-ordination, producing more varied and digestible prose:

Joe bought a dog and the dog barks all night and it keeps us awake.

Co-ordinated main clauses

The dog that Joe bought barks all night and keeps us awake.

Relative subordinate clause

Sometimes, the relative pronoun can be left out, but sometimes it can’t. Click here for details.

Adverbial Clauses

An adverbial subordinate clause modifies the meaning of the main clause in much the same way as an adverb:

  • Although I regret it, I must decline your invitation. (adverbial clause)
  • Regrettably, I must decline your invitation. (adverb)
  • They arrived before it started raining. (adverbial clause)
  • They arrived promptly. (adverb)

Here are the main relationships expressed by adverbial subordinate clauses:


after, as, as soon as, before, once, since, until, when and whenever, while


where, wherever


as, because, since


as, as if, as though, than


as long as, if, in case, provided, provided that

Negative condition

if … not, unless


although, as long as, even if, even though, though, whereas, while


to, in order to, so that


so that, so … that, such … that

Notice that some of these words (those shown in bold) can be used to signal more than one relationship.

Clauses within clauses

A subordinate clause can be at the beginning, in the middle, or at the end of a sentence:

While he was paying for his petrol, his car was stolen.

The teacher who has this group is away today.

His car was stolen while he was paying for his petrol.

Sentences can contain more than one subordinate clause:

While we were away, the girl who was looking after our cat heard that her grandmother had died.

Some of these clauses can be 'nested' one inside another, like Russian dolls or Chinese boxes. For example,

He said that his father went to America because Kate is there.

contains the clause:

(that) his father went to America because Kate is there.

which in turn contains the clause:

because Kate is there.


Pupils can learn how to show nested subordinate clauses in a sentence:

  • by underlining:

  • or using "Chinese boxes":

Non-finite verbs:

  • present participle: sailing

I was sailing (was is finite, sailing is non-finite)

  • past participle: sailed

They have sailed (have is finite, sailed is non-finite)

  • infinitive: to sail, sail

I learned to sail (learned is finite, sail is non-finite)

Watch him sail (watch is finite, sail is non-finite)

Subordinating words

subordinating conjunctions:

after, although, as, as if, as long as, as soon as, as though, because, before, if , in case, in order to, in that, once, provided (that), since, so that, than, that, though, until, unless, when, whenever, where, wherever, whereas, while ... and others.

relative or interrogative pronouns or adverbs

how, that, what, when, where, which, who, whom, whose, why; however, whatever ... and others.

When can a relative pronoun (that) be omitted?


The computer I use at home is faster.

The computer crashed is outside. X

The lesson I like most is English.

The lesson follows this is English. X

The Alice I know has red hair.

The Alice usually sits next to me is his sister. X

The bullet he saw was silver.

The bullet killed him was silver. X

When the noun that the clause refers to is the object of the relative clause and the relative pronoun would have been that, this pronoun can be omitted; but in Standard English it cannot be omitted if it is the relative clause's subject.

What’s left when you remove the subordinate clause?

Look at this sentence:

He burns easily if he doesn’t use sun cream.

This is a main clause, which contains a subordinate clause:

if he doesn’t use sun cream

The meaning intended by the writer or speaker is conveyed by the whole main clause. One part of this main clause is the subordinate clause if he doesn’t use sun cream.

But the remainder "He burns easily" is not a clause on its own; it is part of the whole main clause: He burns easily if he doesn’t use sun cream.

Of course the words he burns easily could stand alone as a main clause in a different sentence, or context, if they conveyed the writer’s full meaning; but in some cases the main clause is grammatically incomplete if we remove the subordinate clause. For example:

He said that it was too late. (Remainder:  X He said.)

Why he did it is unclear. (Remainder:  X Is unclear.)


 Now try an exercise: