Relative Clauses

A number of words related to relative clauses (who, which, that, commas) written in different colours and in different sizes

Relative clauses


One of the features of written academic English that gives it its greater complexity is longer sentences, with more frequent use of subordinate clauses. A clause is part of a sentence and a subordinate clause is a group of words with a subject and a verb that cannot stand alone as a sentence. Relative clauses, both defining and non-defining, are a kind of subordinate clause. Defining ones tell us which thing or person is being referred to, or what kind of thing or person the writer or speaker means. Non-defining ones just add extra, non-essential information about the person or thing being referred to. This Learning Object will provide you with the rules about their use and show you ways that they can sometimes be shortened or replaced by noun phrases to create a more concise style.


  • To provide practice in recognising the two kinds of relative clause
  • To present the rules concerning the different punctuation to use with defining and non-defining relative clauses
  • To provide practice in choosing the correct relative pronoun when using relative clauses
  • To provide practice in forming reduced relative clauses
  • To provide practice in using noun phrases as an alternative to relative clauses

Activity 1: Defining or non-defining? Omitting the relative pronoun?

The rules about using commas, using the relative pronoun “that” and omission of the relative pronoun are different with the two kinds of relative clauses: defining or non-defining.

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By doing the following two exercises, it is hoped that you will gain a greater understanding of the difference between the two kinds of relative clause and then will understand which rules to follow when you are writing your essays.

You may wish to attempt this exercise by referring to the grammatical knowledge you have already acquired. Alternatively, you may like to follow this link Relative Clauses Grammar Rules to refresh your memory of the differences before you do the exercises. Good luck!

Exercise 1. Put a tick in the box if the sentences below are defining relative clauses and leave the box empty if they are non-defining relative clauses.

Exercise 2. In the following defining relative clauses, put a tick if the relative pronoun (‘that’, ‘who’ which’ etc.) can be omitted. If it cannot be omitted, leave the box empty. Remember it is only possible to omit the relative pronoun if it is the object of a defining relative clause.

Activity 2: Choosing the correct relative pronoun/adverb

When you write a sentence with a relative clause, you need to know which of the relative pronouns: “who“, “whom“, “whose“, “which“, “that“, or relative adverbs, “when“, “where” and “why“, to use. We have just seen that it is not possible to use “that” in a non-defining relative clause. Most people avoid using the object form of “who“, which is “whom“, when speaking, but it is sometimes used in writing. However, the possessive form “whose” is used both in speaking and writing. In the exercises that follow, you are going to practise selecting the correct relative pronoun for a number of sentences, which come from academic English sources. You may wish to try these exercises by referring to the grammatical knowledge you have already acquired. Alternatively, you may like to follow this link Choosing Relative Pronouns to refresh your memory of the rules, before you do the exercises. Good luck!

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Choose the correct relative pronoun from the drop down list to fill the gap in each sentence containing a relative clause.

1.) For students ______ background is more creative the treatment of the core subject areas would be more descriptive.

2.) Neither political system could rely with confidence on those to _____ it entrusted the task of educating the peasants.

3.) The court must be satisfied that all persons _______ consent is required understand the legal effect of the adoption.

4.) Finally, one of the students with ______ I had worked a couple of summers previously came back to me, just before I left, to discuss his third year project.

5.) However, in the fifteen to twenty-four age group, many of _____ had probably benefited from education since 1975, the figures were 7.7 and 24.7 per cent respectively.

6.) In Bavaria, most of ______ was overwhelmingly Catholic, by far the greatest unrest was provoked by the crude attempt to remove crucifixes from school classrooms.

7.) It is an area of Belfast _______ routine policing is possible as a result of the virtual absence of political violence.

8.) This is described as the factor _____ “means everything” to the decision about whether or not to proceed.

9.) The third reason ____ Dzerzhinsky was sent off to distant Siberia was purely political, and had little to do with the railways.

10.) It is very unusual to find a tone-unit boundary at a place _____ the only grammatical boundary is between words.

11.) Since 1983, the year _____ the first of a series of large scale mass media campaigns started, the average annual fall has been 2.54%.

12.) The latter makes ______ is already an internally homogeneous organization even more enclosed and protective.

Activity 3: Reduced relative clauses

We have already seen how it is possible to omit the relative pronoun when it is the object of a defining relative clause. In most defining relative clauses where the relative pronoun is the subject, it is possible to omit the relative pronoun and any auxilary verb used to form a tense, then change the verb to a present participle (“-ing“), with an active meaning, or a past participle (usually “-ed“) with a passive meaning. These are called reduced relative clauses and are particularly common in academic English (Biber et al. 1999:606). Follow this link Reduced Relative Clauses for further explanation of when it is possible to change a relative clause to a reduced relative clause and how to do so.

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Rewrite the following sentences so that the relative clauses become reduced relative clauses. Some are active in meaning and will need a present participle, others will need a past participle and the meaning will be passive.

1.) The French verse which is recited to Mrs. Belville is from Voltaire’s adaptation “Nanine”.
2.) Some writing which is called art criticism will be helpful, some will not.
3.) The British reader is likely to have been spared certain of the varieties of suffering which are spoken of in the writings of Kundera and Klima.
4.) Whether a top-down or bottom-up approach is used, this categorization often obscures similarities between items that have been placed in separate categories.
5.) The data and data structures that have been identified can be mapped on to conventional computer files or clerical files and not necessarily databases.
6.) “Push” factors refer to the difficulties of earning a living that were described in the previous chapter.
7.) All the managers’ time was spent on the people who were planning to stay on, so the ones that were planning to leave at the end of the year did not take part in performance appraisal meetings.
8.) The integral (6.24) involves two continuous functions that are monotonically decreasing for positive arguments.
9.) The forms which have been described by King and Williams are characteristic of tideless seas, such as the Mediterranean and the Baltic.
10.) Any letters which contain results and which have arrived late will be forwarded to your home addresses.
11.) None of the clinical symptoms that were recognised as symptoms of primary HIV infection differed between HIV positive drug users and those negative for HIV.
12.) Anyone who will be taking the IELTS examination next month must pay and register at reception before 5 o’clock today.

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© William Tweddle, Queen Mary, University of London, 2010, image generated online by the author using