A relative clause gives more information about someone or something referred to in a main clause. Some relative clauses (defining relative clauses) are used to specify which person or thing we mean, or which type of person or thing we mean:
• The couple who live next to us have sixteen grandchildren.
• Andrew stopped the police car that was driving past.
Notice that we don't put a comma between the noun and a defining relative clause. Relative clauses begin with a relative pronoun: who, which or that. However, sometimes we omit the wh-word that and use a zero relative pronoun
• We went to a restaurant (which/that) Jane had recommended to us.
We prefer to put a relative clause immediately after or as close as possible to the noun it adds information to:
• The building for sale was the house which had a slate roof and was by the stream. (rather than The building for sale was the house by the stream which had a slate roof.)
When we use a defining relative clause, the relative pronoun can be the subject or the object of the clause. In the following sentences the relative pronoun is the subject. Notice that the verb follows the relative pronoun:
• Rockall is an uninhabited island which/that lies north west of mainland Scotland.
• We have a friend who/that plays the piano.
In the following sentences the relative pronoun is the object.
Notice that there is a noun (or pronoun) between the relative pronoun and the verb in the relative clause. In this case, we can use a zero relative pronoun:
• He showed me the rocks (which/that) he had brought back from Australia.
• That's the man (who/that) I met at Allison's party.
We can also use whom instead of who as object, although whom is very formal:
• She's an actress whom most people think is at the peak of her career.
We use that as subject after something and anything; words such as all, little, much, and none used as nouns; and superlatives. (Which is also used as subject after something and anything, but less commonly.) We use that or zero relative pronoun as object after these:
• These walls are all that remain of the city, (not ...all which remain...)
• She's one of the kindest people (that) I know, (not ...who I know.)
• Is there anything (that) I can do to help? (rather than ...anything which I can do...)
You can't add a subject or object to the relative clause in addition to the relative pronoun:
• The man who gave me the book was the librarian, (not The man who he gave me...)
*Notice also that adding a pronoun to the main clause in addition to the relative clause is unnecessary, although it is found in speech:
• A friend of mine who is a solicitor helped me. (or, in speech A friend of mine who is a solicitor - she helped me.)
Some relative clauses are used to add extra information about a noun, but this information is not necessary to explain which person or thing we mean:
• Valerie Polkoff, who has died aged 90, escaped from Russia with her family in 1917.
• We received an offer of £80, 000 for the house, which we accepted.
These are sometimes called non-defining relative clauses. We don't use them often in everyday speech, but they occur frequently in written English. Notice that we put a comma between the Qnoun and a non-defining relative clause, and another comma at the end of this clause if it is not •also the end of a sentence. When we use a non-defining relative clause to add information about a person or people: • we use who as the subject of the clause
• One of the people arrested was Mary Arundel, who is a member of the local council.
We use who or whom as the object of the clause, although whom is more formal and rarely used in spoken English:
• Professor Johnson, who(m) I have long admired, is to visit the university next week.
When we use a non-defining relative clause to add information about a thing or group of things, we use which as the subject or object of the clause:
• These drugs, which are used to treat stomach ulcers, have been withdrawn from sale.
• That Masters course, which I took in 1990, is no longer taught at the college.
That is sometimes used instead of which, but some people think this is incorrect, so it is probably safer not to use it. We also use which to refer to the whole situation talked about in the sentence outside the relative clause:
• The book won't be published until next year, which is disappointing.
• I have to go to hospital on Monday, which means I won't be able to see you.
We can also use whose in a non-defining relative clause:
• Neil Adams, whose parents are both teachers, won first prize in the competition.
Notice that we don't use zero relative pronoun in a non-defining relative clause. When we want to add information about the whole or a part of a particular number of things or people we can use a non-defining relative clause with of which or of whom after words such as all, both, each, many, most, neither, none, part, some, a number (one, two, etc.; the first, the second, etc.; half, a third, etc.) and superlatives (the best, the biggest, etc.):
• The speed of growth of a plant is influenced by a number of factors, most of which we have no control over.
• The bank was held up by a group of men, three of whom were said to be armed.
• The President has made many visits to Japan, the most recent of which began today.
We can use the following phrases at the beginning of a non-defining relative clause: at which point/time, by which point/time, during which time, and in which case:
• It might snow this weekend, in which case we won't go to Wales.
• The bandages will be taken off a few days after the operation, at which point we will be able to judge how effective the treatment has been.
• The next Olympics are in three years, by which time Stevens will be 34.
We use a relative clause beginning with whose + noun, particularly in written English, when we talk about something belonging to or associated with a person.
Compare: • Stevenson is an architect. Her designs have won international praise,
and • Stevenson is an architect whose designs have won international praise.
• Dr Rowan has had to do all his own typing. His secretary resigned two weeks ago.
and • Dr Rowan, whose secretary resigned two weeks ago, has had to all his own typing.
We can use whose in both defining and nondefining relative clauses. We sometimes use whose when we are talking about things, in particular when we are talking about towns or countries, and organizations:
• The film was made in Botswana, whose wildlife parks are larger than those in Kenya.
• We need to learn from companies whose trading is more healthy than our own.
•The newspaper is owned by the Mearson Group, whose chairman is Sir James Bex.
We can also use whose when we are talking about particular items, although it is often more natural in spoken English to avoid sentences like this:
• I received a letter, whose poor spelling made me think it was written by a child. (more natural would be I received a letter, and its poor spelling...)
We often use the words where, when, and whereby as relative pronouns. But in formal English in particular, a phrase with preposition + which can often be used instead:
• This was the place (where) we first met. (or ...the place at/in which we...)
• He wasn't looking forward to the time (when) he would have to give evidence to the court. (or ...the time at which he would...)
• Do you know the date when we have to submit the first essay? (or ...the date on/by which we have to submit the first essay?)
• The government is to end the system whereby (= by which means) farmers make more money from leaving land unplanted than from growing wheat, (or ...the system in/by which farmers...)
We can also use why as a relative pronoun after the word reason. In informal English we can use that instead of why:
• I didn't get a pay rise, but this wasn't the reason why I left, (or ...the reason (that) I left.)
We sometimes use relative clauses beginning with who or what. In this case, who means 'the people that' and what means something like 'the thing(s) that':
• Can you give me a list of who's been invited?
• I didn't know what to do next.
Notice that we can't use what in this way after a noun:
• I managed to get all the books that you asked for. (not ...books what you asked for.)
Relative clauses beginning with whatever (= anything or it doesn't matter what), whoever (= the person/group who or any person/group who), or whichever (= one thing or person from a limited number of things or people) are used to talk about things or people that are indefinite or unknown:
• I'm sure I'll enjoy eating whatever you cook.
• Whoever wins will go on to play Barcelona in the final.
• Whichever one of you broke the window will have to pay for it.
In formal styles we often put a preposition before the relative pronouns which and whom:
• The rate at which a material heats up depends on its chemical composition.
• In the novel by Peters, on which the film is based, the main character is a teenager.
• An actor with whom Gelson had previously worked contacted him about the role.
• Her many friends, among whom I like to be considered, gave her encouragement.
Notice that after a preposition you can't use who instead of whom, and you can't use that or zero relative pronoun:
• Is it right that politicians should make important decisions without consulting the public to whom they are accountable? (not ...the public to who they are accountable.)
• The valley in which the town lies is heavily polluted, (not The valley in that the town...)
• Arnold tried to gauge the speed at which they were travelling, (not ...the speed at they were travelling.)
In informal English we usually put the preposition later in the relative clause rather than at the beginning:
• The office which Graham led the way to was filled with books.
• Jim's footballing ability, which he was noted for, had been encouraged by his parents.
• The playground wasn't used by those children who it was built for.
In this case we prefer who rather than whom (although 'whom' is used in formal contexts). In defining relative clauses we can also use that or zero relative pronoun instead of who or which (e.g. ...the children (that) it was built for). If the verb in the relative clause is a two- or three-word verb (e.g. come across, fill in, go through, look after, look up to, put up with, take on) we don't usually put the preposition before the relative pronoun:
• Your essay is one of those (which/that) I'll go through tomorrow, (rather than ...through which I'll go tomorrow.)
• She is one of the few people (who/that) I look up to. (not ...to whom I look up.)
In formal written English, we often prefer to use of which rather than whose to talk about things:
• A huge amount of oil was spilled, the effects of which are still being felt, (or ...whose effects are still being felt.)
• The end of the war, the anniversary of which is on the 16th of November, will be commemorated in cities throughout the country, (or ...whose anniversary is on...)
Notice that we can't use of which instead of whose in these cases:
• Dorothy was able to switch between German, Polish and Russian, all of which she spoke fluently, (not ...all whose she spoke...)
We can sometimes use that...of instead of of which. This is less formal than of which and whose, and is mainly used in spoken English:
• The school that she is head of is closing down, (or The school of which she is head...)
Whose can come after a preposition in a relative clause. However, it is more natural to put the preposition at the end of the clause in less formal contexts and in spoken English:
• We were grateful to Mr Marks, in whose car we had travelled home, (or ...whose car we had travelled home in.)
• I now turn to Freud, from whose work the following quotation is taken, (or ...whose work the following quotation is taken from.)