How to teach defining and non-defining relative clauses

Summary: How to present and practise relative clauses, including defining and non-defining relative clauses games

Relative clauses like “What’s the English for a thing which opens wine bottles?” and “Jane, who had never met Steve before, was intrigued to find out more” are vital both for classroom communication and for comprehending all but the simplest English texts. However, relative clauses can be tricky to teach, especially if you decide to teach both defining and non-defining relative clauses (like those examples), and even more so if you also get into contact clauses and reduced relative clauses. There are separate articles on this site of teaching each individual kind of relative clause on its own, so this article will give ideas on how to contrast defining relative clauses and non-defining relative clauses in a lesson’s presentation and practice stages.


What students need to know about defining and non-defining relative clauses

Both defining and non-defining relative clauses give extra information about the main clause. However, a defining relative clause gives extra information that you can’t understand the sentence without, whereas a non-defining relative clause just gives optional extra info that may be interesting but could be left out. For example, if I have two brothers and start a conversation with just “My brother is getting a promotion”, you can’t understand which brother I mean without the defining relative clause “My brother who I told you was getting the sack is getting a promotion”. This defining relative clause is, as the name suggests, defining which brother I am talking about. 

However, if I only have one brother or you already know which one I’m talking about, the info about getting the sack is interesting but optional, as in “My brother, who I told you was getting a sack, is getting a promotion”. As which brother is defined in other ways, this is a non-defining relative clause. That it is a non-defining relative clause and that the info is optional is indicated by commas and by a pause and change in tone in speech, in a similar way to how brackets show things which are not essential in sentences like “A ball (the blue one) has gone missing”.

Another contrast between defining and non-defining relative clauses is which relative pronouns can be used. Famously, “that” is not used in non-defining relative clauses, meaning “who” or “which” must always be used instead in sentences like “My fairy godmother, who wasn’t actually a fairy, gave me a Marks and Spencer gift card so I could buy a dress for the ball”. This means that “that” is only used in defining relative clauses.

The same is true about the relative pronoun “why” in “the reason why…”, but as this is the only time that “why” is a relative pronoun, I generally don’t present it at all. You obviously also can’t split “a time when” and “a place where” with commas, but “when” and “where” can be used in some non-defining relative clauses (“Midnight, when the cockroaches dance round the kitchen, always gives me the creeps”, etc). I therefore don’t teach this as a difference.

Other relative pronouns (“which”, “who”, “whose”, “preposition + which”, and “whom” if you decide to teach it) can be used in exactly the same way in defining and non-defining relative clauses.

This all leaves “that” as the only major difference in pronouns between defining and non-defining relative clauses. However, another difference related to pronouns is that relative pronouns cannot be removed from non-defining relative clauses, unlike in defining relative clauses. For example, “which” is optional in sentences like “This is the time (which) I enjoy most of all” but cannot be taken out of “My only big indulgence is cheese, which I spend more on than anything else”.

In contrast, reduced relative clauses (where the relative pronoun and other words such as the auxiliary verb are removed) can be used in both defining relative pronouns (“I’m going to shoot the one drinking black tea”, without “who is”) and non-defining relative clauses (“The sheriff, last seen riding west, seems to have taken all the cash” without “who was”). There is another whole article on reduced relative clauses on this site.

To summarise the differences between defining relative clauses (on the left of each line) and non-defining relative clauses (on the right):

  • necessary information/ optional extra information
  • no commas/ commas
  • no pauses/ pauses
  • no change in tone/ change in tone
  • common relative pronouns are “that”, “which”, “who”, “whose”, “where”, “when” and “preposition + which”/ common relative pronouns are “which”, “who”, “whose”, “where”, “when” and “preposition + which”
  • “that” can be used/ “that” can’t be used
  • relative pronouns can be removed if they are followed by a subject (and as part of a reduced relative clause)/ relative pronouns can’t be removed (unless as part of a reduced relative clause)


How to present defining and non-defining relative clauses

Before deciding how to present this grammar, you’ll need to decide which of the many similarities and differences above you want students to work out and practise. For example, at Intermediate level that could be:

  • that both kinds of relative clause give extra information, but only the info in defining relative pronouns is necessary
  • that the meaning, commas and pron of non-defining relative clauses are similar to the use of brackets
  • that “that” can’t be used in non-defining relative clauses
  • that “which”, “who”, “whose” (and maybe “when” and “where”) can be used with both
  • possibly that the relative pronoun can be taken out of a defining relative clause (but not a non-defining relative clause) before a subject such as “he”

From about Intermediate level, it should be easy to find or simplify a text which has enough examples of relative pronouns to include most of these patterns. Almost any text could work this way, meaning that it’s fairly easy to find one t match the topics that you are covering in the book, but I’ve found that stories and reviews work particularly well.

Students should start with tasks to check their understanding of the text, with at least some of the questions focussing on the parts where the relative clauses are, but with no actual grammar questions yet. They can then look at the text again for how the word “that” is used, how commas are used, etc. You can then use extra individual sentences to add other any useful grammar that is not in the text such as “whose” and “when”, preferably with sentences which are on the same topic as the text.

A slightly more challenging and interesting task after the comprehension questions is for students to be given the same text with the relative clauses taken out and mixed up. Ask the students to put the text back together from memory, logic and their grammar knowledge. You can then discuss why some of the matches weren’t possible, e.g. because we wouldn’t know what was being talked about if a non-defining relative clause was put in a place where more info was necessary. After the analysis stage, they could then put in a few extra relative clauses which you left out of the original text and/ or which you wrote to also go in there.

It is also possible to present all the grammar through separate sentences. Although it is more common to use this idea just for defining relative clauses like “Scissors are things which are used to cut paper”, non-defining relative clauses can also be included in definitions of recent vocabulary like “‘Pension’, which is a noun, means the money that you get when you retire, usually in your 60s”. For the first stage students can simply match the vocabulary to the definitions. Alternatively, for more challenge you can split the definitions into two and get them to match the words to two parts and/ or think about which bits go together. They can then analyse the language in those definitions for what relative pronouns are used, etc.


How to practise defining and non-defining relative clauses

These are all ideas which include both kinds of relative clause in the same activity. Some of the practice tasks, such as the Commas Dictation, could also be used in the presentation stage.


Relative clauses commas dictation

Students listen to the teacher read out the text that they have in front of them and add any missing commas by the logic of the text, their grammar knowledge of what words can and cannot go after commas, and listening for pauses and changes in intonation. They then compare it with the full text with commas, and ask about any which they have missed out or also added. If you do this at the presentation stage, they can then work out why those places and not others have commas in them.


Defining and non-defining relative clauses storytelling card game

Make a pack of cards with a relative pronoun or a just comma on each (including blank cards if you want to practise relative clauses with no relative pronouns). Students read out a first line that their teacher has given them (such as “It was a dark and stormy night”), then take turns continuing the story. While they make the story, they should try to use the words and/ or commas on the cards to change, extend or follow what their partner said, e.g. changing “Lightning flashed across the sky” to “Lightning, which was never seen in that part of the country usually, flashed across the sky” with the “which” card or comma card. To make it into a competition, the cards can either be spread across the table face up for student to take as they use them or dealt out to be discarded as they add them to the story. You could also have a final more challenging stage where they take the cards one by one and can’t take another until they have added that to the story.


Defining and non-defining relative clauses storytelling coin game

This is similar to the game above, but instead of using cards, the next person adds part of the next sentence such as the subject “A dragon”, then flips a coin to decide if there should then be a comma (and so a non-defining relative pronoun – heads) or no comma (and so a defining relative pronoun – tails).


Defining and non-defining relative clauses half bluff

Students make sentences where either the relative clause or the main clause (but not both) are false, then see if other people can spot the wrong information. These can be personal statements, trivia statements and/ or information about vocabulary from the course like “Cautious, which is a noun, is the opposite of reckless”.


Relative clauses longer and longer sentences challenge

Students make or are given a short sentence like “This school is in a suburb” and take turns making it longer by adding extra words, clauses, etc. They continue making it longer and longer until they add something untrue, give up, or need to add a full stop. Both defining and non-defining relative clauses should naturally come up in this game without any specific encouragement.


Defining and non-defining relative clauses crosswords

Students fill in “five down”, “four across”, etc with words and expression that match the definitions which are given. This is another activity that is often used for just defining relative clauses but can be adapted to cover both by sometimes including extra hints like “…, which has seven letters,…” and “…, which starts with P,…” Perhaps after completing an example crossword from the definitions which are given, students can make up crosswords to test other groups with, including such extra hints with non-defining relative clauses in at least half of the questions. If you give them Student A and Student B versions of a crossword with different answers already completed, the same can also be done orally.

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Written by Alex Case for

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