Relative clauses for IELTS Writing and Speaking: rules and errors

A relative clause is a small piece of grammar that does a large amount of work. It turns two short sentences into one and lets you attach a detail to the exact noun it describes. It is also a structure candidates misuse in predictable ways, mostly through punctuation and the choice of “which” or “that”. This guide covers the rules and the errors, then shows where relative clauses help in Writing Task 1, Writing Task 2 and Speaking Part 2. For the criterion as a whole, start with the pillar guide to IELTS grammar.

Why relative clauses matter for the criterion

IELTS.org lists Grammatical Range and Accuracy as one of four equally weighted criteria in Speaking and in Writing. The public descriptors, in this site’s Writing band descriptors explorer and Speaking explorer, say that clauses tucked inside a sentence are rare at the lowest bands. By band 6 the answer mixes short and longer sentences, and at band 7 it uses several kinds of complex sentence.

A relative clause is one of those kinds. It is not required, since IELTS publishes no list of structures and promises no band for any one of them. It is simply the most compact way to attach information to a noun, which is why it appears so often in good scripts.

The basic pattern

A relative clause follows the noun it describes and begins with a relative word. The word stands for the noun, so the clause needs no second reference to it.

In defining clauses you can leave out the relative word when it is the object: “The policy the council introduced reduced traffic”. You cannot leave it out when it is the subject: “The policy that reduced traffic…” needs “that”.

The comma rule

This is a rule candidates often break.

A defining clause tells the reader which noun you mean. It has no commas. “Students who work part-time earn less” means only those students, not all of them.

A non-defining clause adds extra information about a noun that is already clear. It sits between commas. “The village, which lies on the coast, has a small harbour” adds a fact about a village the reader can already identify.

The punctuation changes the meaning. “Workers, who were tired, made more errors” says all the workers were tired. “Workers who were tired made more errors” says only the tired ones did. In Writing, the descriptors also mention punctuation, so a missing or extra comma is both a meaning error and a mark against you.

Two follow-on rules: use “which”, never “that”, after a comma; and when a non-defining clause comes in the middle of a sentence, close it with a second comma.

Reduced relative clauses

Often you can shorten a relative clause by dropping the relative word and the verb “be”, leaving a participle.

• “The graph which shows exports rises sharply” becomes “The graph showing exports rises sharply.”
• “Countries which are affected by drought import more food” becomes “Countries affected by drought import more food.”
• “The figures which are given in the table” becomes “The figures given in the table.”

The first uses an active participle and the next two use a past participle, the same form as a passive. The passive is covered in the guide to the passive voice in IELTS Writing. Reduced clauses suit Writing, where compact sentences read as controlled. In Speaking they are fine, but a full clause with “who” is easier to say at speed.

The common errors

A resumptive pronoun

The relative word already stands for the noun, so repeating it with a pronoun is wrong.

• Wrong: “The man who he lives next door is a doctor.”
• Right: “The man who lives next door is a doctor.”
• Wrong: “The book that I read it was long.”
• Right: “The book that I read was long.”

“Which” for people

Use “who” or “that” for people. “The teacher which taught me” is a frequent slip. Note that “whose” works for both people and things.

A comma on a defining clause

“Students, who study abroad, gain independence” says all students do. If you mean only those who study abroad, remove the commas.

“That” after a comma

“The tower, that opened in 1990, …” should be “The tower, which opened in 1990, …”.

A “which” that refers to the wrong thing

“Which” can refer to a whole clause, as in “Prices rose, which surprised nobody”. The error comes when the reader could attach it to the noun nearer to it.

• Unclear: “The government built a road near the school, which was a mistake.” Was the road, the school, or the decision a mistake?
• Clearer: “The government built a road near the school, a decision which proved to be a mistake.”

When you write a “which” at the end of a sentence, read back to the previous noun and ask whether the reader could attach it there by accident.

A clause that never ends

“The city which has a large population and many factories and…” has no verb for “the city”. In Speaking this happens when you start a clause and lose the thread, which the band 5 explorer cells describe as beginning a long structure with no plan for how it ends. Keep the clause short enough to finish.

Where relative clauses help

Task 1: describing a feature

In Task 1 you describe a visual, and you will often need to say something more about a line, a bar or a place. A relative clause lets you do that without a new sentence. Invented examples:

• “The line for rail travel, which starts at the lowest point, overtakes road travel in the final year.”
• “The map shows a village where a new road replaces the old market.”

See the guide to Task 1 charts, graphs and tables for how to choose what to describe. A relative clause should add a detail you were going to mention anyway, not decorate.

Task 2: qualifying a claim

In an essay, a relative clause qualifies a general claim so that it becomes accurate. “Governments that invest in rail reduce congestion” is more defensible than “Governments reduce congestion by investing in rail”, because it limits the claim to those that invest. The qualification is the argument.

Speaking Part 2: adding detail

The Part 2 long turn rewards a story with detail. A relative clause adds the detail while keeping the story moving: “a teacher who changed how I studied”, “a town where nothing seemed to happen”. Compare the advice in the post on common grammar mistakes in Speaking: the goal is a clause you can finish correctly at speaking speed, not a long one.

Practise one at a time

Take three pairs of short sentences from your own writing and join each pair with a different relative word. Then check each result against the list above: is the noun right, is the comma rule followed, is there a leftover pronoun? The complex sentences guide shows the other main way of joining clauses, and the guide to linking words shows how joins serve coherence.

Once you have a draft, read it out loud. A clause that sounds unfinished usually is.