Relative Clauses in English Grammar

Introduction

Relative clauses allow us to provide additional information without having to start a new sentence. In English, there are two types of relative clauses: defining relative clauses, used without commas, and non-defining clauses which are set off by commas.

Learn about defining and non-defining relative clause with Lingolia’s grammar lesson. Then test your knowledge in the exercises.

Example

These are my friends who I spend a lot of time with.

The boy who is wearing glasses is Tony.

Phil, who I met at summer camp, is very funny. I can still remember the day when I met him.

We have a youth club in town where I often meet my friends. This is the reason why I go there.

They often have a disco in the club, which is very popular. Linda, whose mother is a ballerina, can dance very well.

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Usage

Relative clauses include additional information about a subject or object, and they usually come directly after the subject/object to which they refer.

Example:
The boy who is wearing glasses is Tony.

The boy is Tony. Tony is wearing glasses.

Construction of Relative Clauses

Relative clauses are introduced by a relative pronoun or a relative adverb.

Relative Pronouns

relative pronounsusageexample sentence
who as subject or object for people the boy who is wearing glasses
which as subject or object for animals and things in non-defining relative clauses … in the club, which is very popular
whose possession/belonging, for people, animals, and things the girl whose mother is a ballerina
whom quite formal, as object for people, especially in non-defining relative clauses Phil, whom I met at summer camp
that as subject or object for people, animals, and things in defining clauses (who and which are also possible) the boy that is wearing glasses

To Note

In colloquial language, who commonly replaces both subjects and objects. In formal language, however, it is still considered more correct to say whom when referring to the object of a sentence. If we choose whom, then the preposition comes at the beginning of the relative clause.

Example:
Phil, who I met at the summer camp, is very funny.
→ Phil, whom I met at the summer camp, is very funny.
These are my friends who I spend a lot of time with.
→ These are my friends with whom I spend a lot of time.

Subject or object?

Who, which, that can replace a subject or an object, it is easy to figure out which one they stand for:

  • If a verb comes directly after the relative pronoun, then the relative pronoun replaces a subject and must be used.
    Example:
    the boy who is wearing glasses
  • If there is no verb directly after the relative pronoun (but rather a noun or a pronoun instead), then the relative pronoun replaces an object and can be left out in non-defining clauses (contact clauses).
    Example:
    the boy (who/whom) I met at the summer camp

Relative Pronouns with a Preposition

If we use the relative pronouns with a preposition, the preposition usually comes at the end of the relative clause.

Example:
These are my friends who I spend a lot of time with.

Except when the relative pronouns is whom, in which case, the preposition comes at the beginning of the relative clause.

Example:
These are my friends with whom I spend a lot of time.

When describing a place, time, or reason, the preposition also comes at the beginning of the relative clause. However, it is more common to use relative, see below.

Example:
I can still remember the day on which I met Phil.
This is the youth club in which I meet my friends.
This is the reason for which I go there.

Relative Adverbs

Relative adverbs can refer to an entire clause, or to a time, place, or reason in which case they are replacing a preposition + which.

Example:
I can still remember the day when I met Phil.
(instead of: I can still remember the day on which I met Phil.)
relative adverbreplacesmeaningexample sentence
which refers to the entire clause Linda dances well, which doesn’t surprise me.
when in/on which a point in time is more precisely described I can still remember the day when I met Phil.
where in/at which a place is more precisely described This is the youth club where I meet my friends.
why for which a reason is more precisely described That’s the reason why I go there.

Defining and Non-Defining Relative Clauses

In English we differentiate between defining and non-defining relative clauses.

Defining Relative Clauses

Defining relative clauses are also known as identifying relative clauses or restrictive relative clauses in English, and are used without a comma. They are therefore necessary, because they define something more precisely.

Example:
The boy who is wearing glasses is Tony.

Since there are two boys in the picture, we wouldn’t know which one was Tony if we didn’t have the relative clause.

Non-Defining Relative Clauses

Non-defining relative clauses are also known as non-identifying relative clauses or non-restrictive relative clauses in English, and are used with commas. They are therefore not necessary, because even without the relative clause we would still understand who or what is being referred to.

Example:
Phil, who I met at summer camp, is very funny.

A name is usually enough to identify a person, so the relative clause is not being used for purposes of identification, but merely to add some additional information about Phil. However, if both boys were called Phil, then we would need a defining relative clause to indicate which Phil we were talking about.

To Note

In non-defining relative clauses, who/which may not be replaced by that.

not:
Phil, that I met at summer camp

Contact Clauses

When an object is replaced in a defining relative clause, we can leave out the relative pronoun who/which/that. This kind of relative clause is known as a contact clause.

Example:
The boy and the girl are friends. I spend a lot of time with them.
→ These are the friends (who/whom) I spend a lot of time with.

But be careful! We have to keep the relative pronoun …

  • when it replaces a subject
    Example:
    Tony is a boy. He is wearing glasses.
    → The boy who is wearing glasses is Tony.
    (not: The boy is wearing glasses is Tony.)
  • in a non-defining relative clause
    Example:
    Phil, who I met at summer camp, is very funny.
    (not: Phil, I met at summer camp, is very funny.)