Relative Clauses
1. General description
We use relative clauses to give extra information about someone or something in the main clause of the sentence.
There are two types of relative clauses:
Defining relative clauses specify / define which thing or person we mean exactly.
Non-defining relative clauses simply add extra information.
The relative clause can refer to the subject or the object of the main clause, or it can be possessive.
Relative clauses use the relative pronoun. Look at the table for a summary of the relative pronouns.
| Defining | Non-defining | ||
| Person | Thing | Person | Thing |
Subject | who / that | which / that | who | which |
Object | ø / who(m) / that | ø / which / that | who(m) | which |
Possessive | whose | whose (of which) | whose (of which) | whose |
Place | (preposition) which / where | (preposition) which / where / | ||
Reason | why / ø | why | ||
Time | When / ø | when | ||
Note:
Who and which are more common than that in writing.
The relative pronoun is often omitted in defining relative clauses.
Whom is formal and is preferred in writing.
2. Defining relative clauses
We use defining relative clauses to give information which is necessary in order to identify or specify a thing or person. We don’t use commas in defining relative clauses.
We can omit the relative pronoun in object position. However, where cannot be omitted.
The woman who / that is standing in the corner is waiting for her friends.
The man whose car has just been stolen is speaking to the police.
The car which / that is parked there is brand new.
The cake that / which / ø you made me was delicious!
The reason why / ø he died will never be known.
Compare:
That’s the restaurant where we celebrated our anniversary.
That’s the restaurant which / that / ø we like best.
3. Non-defining relative clauses
We use non-defining relative clauses when the information we want to give is not essential and can be omitted. The main clause makes sense without the relative clause.
We use a comma before the relative pronoun. The relative pronoun cannot be omitted.
My neighbour, who is a very quiet person, is moving to a different town.
Pancakes, which is my favourite treat, is made with flour, milk and eggs.
London, where I grew up, has experienced bouts of hot weather recently.
4. Comment clauses
We can add a non-defining relative clause to the end of the sentence by using which. This way we can refer to the whole clause (add a comment). This is very common in spoken English.
Jack lost his job when the company went bankrupt, which is rather unfortunate.
In spoken English, we can also use the comment clause to add our opinion.
A: The plane was cancelled because of the sudden snow storm and we had to sleep at the airport!
B: Which must have been awful!
5. Modifying the relative pronoun
In non-defining relative clauses, we often use quantifiers before which and whom to refer to the subject or object.
many most all several half none neither part a number one / two / three, etc. the first / the second, etc. | of | which whom |
The guests, many of whom travelled from far, waited anxiously to see the speaker.
I have over a hundred student, all of whom have passed their exams.
6. Using determiners
We usually use that (not which) after certain determiners and after superlatives. In object position, that can be omitted.
all / any(thing) / every(thing) / few / little / many / much / no(thing) / none / some(thing)
There was nothing that could have been done.
It was the most difficult exam (that) I have ever taken.
All (that) I knew was that Jane had left the country.
7. Whichever, whenever, etc.
We can modify the relative pronoun with -ever in defining relative clauses to give the meaning of anything, anyone, anywhere, etc.
Take whichever pen you want. (=any pen that you want)
I want you to tell me whatever you know about it. (anything that you know)
8. Relative clauses and prepositions
We can use prepositions with the relative pronouns. In informal English, the preposition usually comes at the end of the relative clause. In formal English, the preposition goes before the relative pronoun.
We don’t put a preposition before that.
The taxi in which we travelled to the airport was a Mercedes. (formal)
The taxi (which) we travelled to the airport in was a Mercedes. (informal)
Einstein invented the theory of relativity in 1905, for which he will always be admired.
Examples of the most common formal form:
Informal | Formal |
a period when a time that / a time when where where whose purpose why | a period during which a time during which in which / on which by which / whereby the purpose of which the main reason for which |
9. Who or whom?
We use who and whom to refer to the subject of the relative clause. We always use whom after the preposition. Whom is more formal than who.
The man at whom she smiled asked her for a dance.
The man who / whom she smiled at asked her for a dance.
My boss, to whom I mentioned the problem, doesn’t know what to do.
My boss, who / whom I mentioned the problem to, doesn’t know what to do.
10. Prepositional phrases
We can use prepositional phrases to replace the relative clause.
Only employees with advanced degrees can be promoted. (employees who have …)
The house on the corner has been renovated. (the house which is…)
11. Adjective phrases
We can use adjective phrases to replace the relative clause. Often the adjective is followed by a preposition, a to- infinitive, or an adverb.
You can use any material available freely to package the books. (any material which is available)
It’s a task difficult even for the most experienced engineer. (a task which is difficult)
Ready to test your knowledge?
Put the grammar rules above into practice with the challenge below.
