In both the IELTS Writing and Speaking tests, it’s important to use a range of grammatical structures, including both simple and complex sentences.
When you use complex sentences accurately, you show the examiner that you know English well, which can help you achieve a higher IELTS band score.
What is a complex sentence?
Simple sentences contain one complete thought. They have one or more subjects and one or more verbs. Grammar books call these independent clauses.
On the other hand, complex sentences contain one independent clause and at least one dependent clause. A dependent clause is a group of words that contains a subject and verb but does not make sense on its own. Instead, it relies on the independent clause to show a complete idea. The dependent clause adds more information to the sentence, but it cannot stand alone as a sentence.
Independent Clause: A complete sentence that can stand alone.
Example: He ate his dinner.
Dependent Clause: A clause that cannot stand alone.
Example: Before he went to the cinema.
How to make complex sentences
A dependent clause can come first or second in complex sentence.
He ate his dinner before he went to the cinema.
or
Before he went to the cinema, he ate his dinner.
If the independent clause comes first, you don’t need to include a comma.
He ate his dinner before he went the cinema.
If the dependent clause comes first, put a comma between the two clauses.
Before he went to the cinema, he ate his dinner.
Dependent clauses start with a subordinating conjunction. These are linking words like before, even though, if, unless, because, whereas, when etc.
Types of complex sentences
Complex sentences are useful for showing relationships between ideas, such as cause and effect, contrast, or conditions. Here are some common examples:
Example | Independent clause | Dependent clause | Type of complex sentence | Examples of subordinating conjunctions |
|---|---|---|---|---|
We had to take a taxi because we missed the bus. | We had to take a taxi | because we missed the bus. | Cause and effect | because, since, as |
Although tourism boosts local economies, it can lead to environmental damage. | it can lead to environmental damage. | Although tourism boosts local economies | Contrast | although, even though, though, whereas, while |
If more people used public transport instead of driving, air quality could improve. | air quality could improve | If more people used public transport instead of driving | Condition | if, unless, as long as, provided that, in case |
We’ll go for a walk as soon as the rain stops. | We'll go for a walk | as soon as the rain stops. | Time | as soon as, before, after, once, until, when, while |
Tips for using complex sentences in your IELTS test
Using complex sentences effectively in your IELTS test can showcase your language proficiency and improve your overall score. Try these three tips for including complex sentences in your writing:
Practise sentence combining: Before your IELTS test, practise combining simple sentences into complex ones by using conjunctions. Ask a teacher for feedback.
Vary sentence structure: While it’s important to use complex sentences in your IELTS Writing test, avoid overusing them. Aim to include a mix of sentence types in your responses. This demonstrates your ability to use English flexibly.
Check for errors: Leave at least five minutes at the end of your Writing test to review your sentences for errors. Complex sentences can be more challenging to construct correctly. Look out for mistakes with punctuation, conjunctions and subject-verb agreement. Try our short quiz below to practise spotting common errors in complex sentences.
Complex sentences quiz
Can you correct one mistake in each complex sentence? You can find the answers at the end of the quiz.
Q1: While travelling offers the chance to experience new cultures it can be expensive.
Q2: You can borrow the car unless you return it with a full tank of petrol.
Q3: The service was quick, even though the restaurant was busy.
Q4: Since the company provides flexible hours, staff wear uniforms.
Q5: Although the hike was challenging, but the view at the top made it worthwhile.
Answers to quiz
Q1: While travelling offers the chance to experience new cultures, it can be expensive.
Explanation: When a sentence begins with a subordinating conjunction, add a comma between clauses.
Q2: You can borrow the car if/as long as/provided that you return it with a full tank of petrol.
Explanation: Unless means ‘if not.’ We can only use it in this sentence if we change it to a negative situation. For example: You can’t borrow my car unless you return it with a full tank of petrol.
Q3: The service was quick even though the restaurant was busy.
Explanation: When a subordinating conjunction is used in the middle of the sentence, we don’t need a comma.
Q4: Example correction (other options are possible): Since the company provides flexible hours, staff are able to manage their personal commitments more effectively.
Explanation: The two clauses need to be related in meaning. No connection is made between flexible hours and uniforms, so the sentence needs to be rewritten.
Q5: Although the hike was challenging, the view at the top made it worthwhile.
Explanation: Too many conjunctions. Remove but as the word although is being used to show contrast.
Final thoughts
Remember, using complex sentences can improve both your writing and speaking, but use them wisely. Focus on using a range of sentence structures to communicate your ideas clearly and accurately and you’ll be well-positioned to achieve your desired score in your IELTS test.