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A group of words that has a subject and a verb is called a clause. A clause may or may not be a complete sentence. There are two kinds of clauses: independent clauses and dependent clauses.

An independent clause, or main clause, is a complete sentence. It contains the main subject and verb of the sentence.

  • Alex goes to work.
  • The children are doing their homework.
  • It turned quite cold.

In addition to the subject and verb of a clause, other elements may be added to the beginning, middle, or end of the clause to provide more information. These elements can be adverbs, prepositional phrases, or even other clauses.

ADVERBAlex rarely goes to work.
PREPOSITIONAL PHRASEIn the summer, Alex goes to work on his bike.
RELATIVE CLAUSEAlex, who is my husband’s best friend, goes to work
with me.

dependent clause cannot stand on its own and make complete sense. It must be connected to an independent clause. Consider the following examples, which sound strange when they stand alone; they are dependent on another clause to complete their meaning.

  • Although he likes it a lot.
  • When we visited Portugal.
  • Since he arrived here last June.
  • While the baby was still asleep.

These clauses have a subject and a verb, but they do not express a complete idea. A dependent clause, by itself, is called a sentence fragment.

You can often recognize a dependent clause by the presence of a subordinating conjunction. “Because he is on time” is a dependent clause, whereas “He is on time” is an independent clause.

The following sentences combine the dependent clauses in the examples above with independent clauses to make complete sentences.

  • Although he likes it a lot, he won’t spend that much for the car.
  • When we visited Portugal, we came upon a beautiful mountain village.
  • Since he arrived here last June, he has refused to go out and find a job.
  • John and Mary cleaned up the family room while the baby was still asleep.

Following is a list of the most common conjunctions that could begin a dependent clause.

aseven thoughthoughwhether
as long asifunlesswhile
as soon asin order thatuntil

The relative pronouns who, which, and that also introduce a dependent clause.

relative clause is a dependent clause that modifies an antecedent noun or pronoun in an independent clause. It identifies, describes, or otherwise provides information about the antecedent.

The subject pronouns for a relative clause are who, which, and that. In the following examples, note how two independent sentences are connected by a relative pronoun to make one single complete sentence.

  • I thanked my dad. My dad brought me my house keys.
  • I thanked my dad, who brought me my house keys.
  • They live in Seattle. Seattle is on the Pacific Ocean.
  • They live in Seattle, which is on the Pacific Ocean.
  • She has the information. The information will clear my name.
  • She has the information that will clear my name.

If the same noun or pronoun occurs in two sentences as illustrated above, the second clause can be changed to a relative clause by combining the two clauses with a relative pronoun. The repeated noun or pronoun in the second clause is changed to a relative pronoun.

Note that the subject or object of two such clauses can be considered identical even if one is the pronoun replacement of the other.

  • The laptop is mine. It is on the table.
  • The laptop that is on the table is mine.
  • I spoke with her mother. She said that Laura was out of town.
  • I spoke with her mother, who said that Laura was out of town.

Who is used for people, which is used for things, and that is used for both people and things. But there is another difference to be considered between who, which, and that. Who and which introduce relative clauses that are parenthetical in nature—they provide nonessential information about the antecedent.

  • The governor, who is visiting Canada right now, was elected in a landslide.
  • This orchard, which was planted by my grandfather, produces 1,000 bushels of apples each year.

The relative pronoun that introduces a clause that provides essential information about its antecedent.

  • The governor that was recently elected received a standing ovation.
  • The orchard that was destroyed by insects was planted by my grandfather.

Commas separate a clause introduced by who or which, but not a clause introduced by that.

If the relative pronoun is an object in the relative clause, who is changed to whom in formal speech and writing; whom is not often used in casual speech. When the relative pronoun that is the object of its clause, it can be omitted.

  • The men that they rewarded for their bravery are out of work.
  • The men they rewarded for their bravery are out of work.
  • The watch that he found on the sidewalk is priceless.
  • The watch he found on the sidewalk is priceless.

Prepositions, which require the object form of who and which, can stand in more than one position in a relative clause: at the beginning or the end.

  • The men about whom she plans to write an article are out of work.
  • The men that she plans to write an article about are out of work.
  • The article from which we got the information is about global warming.
  • The article that we got the information from is about global warming.

If the relative pronoun is that, the position of the preposition is always at the end of the clause and that can be omitted.

  • The books that you asked for are on your desk.
  • The books you asked for are on your desk.

Indefinite relative pronouns

Compound forms of the relative pronoun—whoever, whomever, whatever, and whichever—are called indefinite relative pronouns, because they do not refer to a specific person or thing.

  • Whoever finishes first wins a prize. (one of the contestants)
  • The manager selects whomever she wants for the job. (one of the employees)
  • The man just blurted out whatever came to mind. (one of his thoughts)
  • Pick whichever of the two books interests you. (one of the books)

Who and what can also be used as an indefinite relative pronouns. They replace the old-fashioned and awkward phrases him who and that which.

  • I don’t know him who arrived. ; I don’t know who arrived.
  • I’ll tell you that which is important. ; I’ll tell you what is important.

Indefinite who and what can also be used as objects in a relative clause.

  • Mr. Cole asked about whom the letter was written.
  • They announced who the new chancellor will be.
  • She didn’t understand what you were talking about.
  • Do you have any idea what the woman wanted?

Possessive relative pronouns

Whose is used to indicate possession. Like other possessive pronouns (my, your, his, her, its, our, their), it is used to modify a noun. The possessive pronoun and the noun are placed at the beginning of the relative clause.

  • I know this lady. Her purse was stolen.
  • I know this lady whose purse was stolen.
  • The man paints well. I saw his exposition.
  • The man, whose exposition I saw, paints well.

Whose may also replace a possessive noun.

  • They located the woman. The woman’s mother had become ill.
  • They located the woman whose mother had become ill.
  • Can you help the tourists? The tourists’ visas have expired.
  • Can you help the tourists whose visas have expired?


In a relative clause, where refers to a place in the independent clause and replaces a prepositional phrase indicating location. The preposition from the phrase replaced by where is not used.

  • The house is new. He lives in the house.
  • The house where he lives is new.
  • The house, in which he lives, is new.
  • The house, which he lives in, is new.
  • The house that he lives in is new.
  • The house he lives in is new.
  • The barn caught fire. They were playing inside the barn.
  • The barn, where they were playing, caught fire.
  • The barn, inside which they were playing, caught fire.
  • The barn, which they were playing inside, caught fire.
  • The barn that they were playing inside caught fire.
  • The barn they were playing inside caught fire.

Where may also replace there in such clauses.

  • The house is new. He lives there.
  • The house where he lives is new.


In a relative clause, when refers to a time expression in the independent clause and replaces an adverbial expression of time. The preposition accompanying a noun (on that day, in that year, at that time, in that century, and so on) is used before which. Otherwise, the preposition is omitted. When may also replace then in such clauses.

  • I’ll never forget that day. I cried a lot that day. (I cried a lot then.)
  • I’ll never forget that day, when I cried a lot.
  • I’ll never forget that day, on which I cried a lot.
  • I’ll never forget that day that I cried a lot.
  • I’ll never forget that day I cried a lot.

Time expressions use various prepositions, but when replaces the entire prepositional phrase, including the preposition.

  • She came in May. The weather is better then.
  • She came in May, when the weather is better.
  • It happened on Monday. He was still at home then.
  • It happened on Monday, when he was still at home.
  • I’ll be there next week. Exams will be finished next week.
  • I’ll be there next week, when exams will be finished.
  • Everyone left the party. The band stopped playing after the party.
  • Everyone left the party when the band stopped playing.

Relative clauses that modify pronouns

Relative clauses can modify indefinite pronouns; the relative pronoun is usually omitted when it is the object of the clause.

  • Anybody who wants to come is welcome. (SUBJECT)
  • There is someone I want to talk to. (OBJECT)
  • Everything he paints is ugly. (OBJECT)

Other indefinite pronouns that follow this pattern are anything, everyone, no one, and nothing.

Relative clauses can also modify the one(s) and those. The relative pronoun is used when it is the subject of the clause.

  • Financial aid is available for those who really need it. (SUBJECT)
  • Jeffrey was the only one I knew at the meeting. (OBJECT)

Expressing quantity in relative clauses

Quantity can be expressed in a relative clause with the preposition of following an expression of quantity, such as most, many, or some. The relative pronoun (whom, which, or whose) follows of.

  • In my office, there are 12 people. Most of them are graduate students.
  • In my office, there are 12 people, most of whom are graduate students.
  • She gave us several tips. Only a few of them were useful.
  • She gave us several tips, only a few of which were useful.
  • The team captains discussed John. One of his problems was lack of discipline.
  • The team captains discussed John, one of whose problems was lack of discipline.

Following are some commonly used expressions that can introduce quantity in a relative clause.

all of(a) few ofmost ofa number of
both of(a) little ofneither ofsome of
each ofmany ofnone oftwo of

Noun + of which

A relative clause may begin with a noun followed by of which. This construction, which is primarily used in formal written English, is a form of the possessive.

  • He has an antique Japanese table. The top of it is made from ebony.
  • He has an antique Japanese table, the top of which is made from ebony.

In less formal style, the sentence would be as follows.

  • He has an antique Japanese table, whose top is made from ebony.

Which as the relative pronoun for an entire clause

An entire clause can be referred to by the relative pronoun which. This occurs when the relative pronoun refers not to one element in the main clause, but to the entire concept described in that clause.

  • Robin was early. That surprised everyone.
  • Robin was early, which surprised everyone.

In this example, no one was surprised by Robin. No one was surprised by the early (time). But everyone was surprised by the entire idea that Robin was early. The antecedent of which is, therefore, the entire main clause.

  • The escalator is out of order. This is rather inconveniencing.
  • The escalator is out of order, which is rather inconveniencing.
  • Both Tom and Laura won prizes. That made Dad very proud.
  • Both Tom and Laura won prizes, which made Dad very proud.
  • Marco falls asleep in class every day. This is unacceptable.
  • Marco falls asleep in class every day, which is unacceptable.

Noun clauses

noun clause can be used as a subject or an object. It is composed of a noun and other elements that are used as a single entity—the subject or object of the sentence.

What he brought was beautiful.I saw what he photographed.
What he brought back was beautiful.I saw what he photographed with an old camera.
What he brought back in his suitcase was beautiful.I saw what he skillfully photographed with an old camera.

Following is a list of words that can introduce noun clauses.


Noun clauses that begin with a question word

Noun clauses can be used as part of a response to a question.

QUESTIONWhere do they study?
RESPONSEI don’t know where they study.
QUESTIONWho built this castle?
RESPONSENo one has any idea who built this castle.

When used as a noun clause, the original question becomes either the subject or the object of the new sentence.

SUBJECTWhat she thought about Bill was best kept a secret.
OBJECTI have no idea what she thought about Bill.

Whereas do, does, and did are used to form questions with many verbs, they are never used in a noun clause.

QUESTIONWhat did she buy at the store?
RESPONSEI don’t know what she bought at the store.
QUESTIONWhat time does Tom’s plane arrive?
RESPONSEMom knows what time Tom’s plane arrives.

Note that the subject of a noun clause always precedes the verb, whether the question word is the subject or not. The question word is always the first element of a noun clause.

  • Who is in the backyard? (SUBJECT = who)
  • I wonder who is in the backyard.
  • What is she doing? (SUBJECT = she)
  • What she is doing is terribly wrong.
  • Where are the boys now? (SUBJECT = boys)
  • No one knows where the boys are now.
  • On what day will they arrive? (SUBJECT = they)
  • I know on what day they will arrive.

Noun clauses that begin with whether or if

Whether or if is used to introduce a clause when a yes/no question is changed to a noun clause. If often replaces whether in casual speech.

  • Will they come?
  • I don’t know whether they will come.
  • I don’t know if they will come.
  • Does she need assistance?
  • I wonder whether she needs assistance.
  • I wonder if she needs assistance.

The phrase or not is sometimes included in the noun clause.

  • I wonder whether or not they will come.
  • I wonder whether they will come or not.
  • I wonder if she will come or not.

Noun clauses that begin with that

That can introduce a noun clause. It has no meaning per se, which is why it is often omitted, particularly in spoken English.

  • She is a good cook.
  • We all think that she is a good cook.
  • We all think she is a good cook.
  • The sea is blue.
  • I know that the sea is blue.
  • I know the sea is blue.

However, that cannot be omitted if the noun clause is used as the subject of the sentence.

  • She doesn’t like silent movies.
  • That she doesn’t like silent movies comes as a surprise to me.

The pronoun it often introduces a main clause that is followed by a noun clause introduced by that.

  • It comes as a surprise to me that she doesn’t like silent movies.
  • It is well known that there is corruption at City Hall.

Question words and infinitives

Question words and whether may be followed by infinitives. The infinitive replaces the subject of the clause plus should, can, or could.

  • Peter can’t decide whether he should go or stay at the office.
  • Peter can’t decide whether to go or (to) stay at the office.
  • I don’t know whether I should laugh or cry.
  • I don’t know whether to laugh or (to) cry.
  • Please tell her how she can get to the nearest post office.
  • Please tell her how to get to the nearest post office.
  • Alicia told me where I could buy a cheap scooter.
  • Alicia told me where to buy a cheap scooter.

The subjunctive

After certain main verbs, a noun clause beginning with that requires its verb to be subjunctive. The subjunctive form of a verb is its base form, for example, run, be, and show.

  • The law demands that we be fair.
  • I insisted that she stop by my house.
  • I suggested that he not go to the football game.
  • It is important that she be told where to sit.

Following is a list of common verbs and expressions that require a subjunctive verb in a noun clause introduced by that.

advise (that)it is essential (that)recommend (that)
ask (that)it is important (that)request (that)
demand (that)it is necessary (that)suggest (that)
insist (that)it is vital (that)
it is crucial (that)propose (that)

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