We use relative clauses to give additional information about a noun, such as a person or a thing.
We can combine (or join) two sentences to make one sentence of two clauses. One of the clauses is the main clause and the other is the subordinate clause (or relative clause).
Relative pronouns introduce a relative clause. They include:
The relative pronoun who is used to refer to people. It can replace both subject and object of the clause.
However, in formal English (written and spoken), the relative pronoun whom (NOT who) is used to refer to the object of the clause.
We use the relative pronoun which to refer to all nouns except people.
The relative pronoun that is commonly used in place of who, whom and which in defining relative clauses.
In non-defining clauses, only who, whom and which can by used.
The relative pronoun whose is used to show that the noun in the main clause owns or is related to the noun in the relative clause.
It is used instead of possessive adjectives (my, your, our, his, her, its, their) with people, things and animals.
Note: The relative pronoun whose is different from who’s,
Who’s (with apostrophe ‘ ) is the short form of who is or who has.
See more explanation of the difference between the two words in the Grammar FAQs page.
In very formal English, the preposition can come before the relative pronoun at the beginning of the relative clause. In this case, whom (NOT who) is used after the preposition.
And here is another example:
This is an example with which:
There are two types of relative clauses that describe the nouns: defining and non-defining relative clauses.
In addition, relative clauses can refer to a whole sentence or clause, especially in speaking.
Defining relative clauses add essential information about a noun.
If we remove the defining relative clause, the sentence does not make sense.
Non-defining relative clauses add extra information to a noun or noun phrase.
This extra information is not essential.
If we remove the relative clause, the sentence still makes sense.. This type of clause is more common in written English.
The structure of both defining and non-defining relative clauses is the same. But they are different in the use of punctuation.
With non-defining relative clauses, we separate the clause with commas.
Also, we cannot use that in this type of clause.
When we combine two sentences into one sentence of two clauses (main clause and relative clause), we place the relative clause close to the noun that it describes.
In the two examples above, the nouns we want to describe come at the end of the first sentence. So we had only to remove the full-stop and put the relative pronoun instead of the subject of the second sentence.
Sometimes the relative clause describes the subject of the main clause. In these cases, we insert the relative clause after the subject and before the main verb of the main clause.
Relative clause can refer to a whole sentence or group of sentences. (That’s why they are sometimes called sentential relative clauses ).
We introduce this type of relative causes with the relative pronoun which.
In writing, we add a comma before which.
In speaking we sometimes pause before which clauses.
In informal speaking, we use which to express an opinion or evaluation of what has been said.
In the conversation below, the first speaker (A) comments with a which clause after the listener (B) responded.
In informal speech and writing, we can completely leave out the relative pronoun in defining relative clauses only when it refers the object of the relative clause.
In the following example, however, we cannot omit the relative pronoun because it replaces the subject of the defining relative clause.
On the other hand, we cannot leave out the relative pronoun in non-defining relative clauses
Relative adverbs describe time, place and reason. They are:
They introduce relative clauses, and they usually replace the formal structure preposition + relative pronoun, such as on which, at which, for which, etc.
We use when after words that refer to time, such as year, day, time, moment, winter, etc.
It can be omitted or replaced by that.
We use where after words that refer to place, such as place, house, school, town, country, etc.
We use why before the reason of something.
Here are some common errors people make when they use relative clauses and pronouns and how to correct them.
1. using a pronoun or noun along with the relative pronoun when it is a subject
Χ Where are the boys who they will play with us?
√ Where are the boys who will play with us?
2. leaving out the relative pronoun when it is the subject of the relative clause
Χ This is the man won the first prize.
√ This is the man who won the first prize.
3. keeping the object in the relative clause along with the relative pronoun that refers to it
Χ I will bring the book that you lent me it.
√ I will bring the book that you lent me.
4. not using commas to separate a non-defining clauses in writing
Χ She was reading Hamlet which was written by Shakespeare.
√ She was reading Hamlet, which was written by Shakespeare.
5. using commas to separate defining clauses in writing
Χ He works in a company, that is located in his hometown.
√ He works in a company that is located in his hometown.
6. using which to refer to adverb of time or place without a preposition
Χ Do you remember the day which we received the offer?
√ Do you remember the day on which we received the offer?
√ Do you remember the day when we received the offer?