How To Write A Complex Sentence

Originally published December 2017. Last reviewed 3 July 2026.

In this post, we will look at how to use complex sentences in your IELTS writing task 2 essay. Being able to include complex sentences in your writing is important because it shows the examiner that you know how to use them effectively. This can increase your band score in the grammatical range and accuracy section.

In order to gain a band score 7, you need to be able to show the examiner that you can ‘use a variety of complex structures’. For the higher band scores of 8, you need to ‘use a wide range of structures’ and for a band score 9 ‘use a wide range of structures with full flexibility and accuracy’. This means that you should include complex sentences in your essay, but you do not have to make all of your sentences complex. 

What Is A Complex Sentence?

Complex sentences are when two or more basic sentences are joined together, using connecting words. Below you will see four simple sentences:

Simple Sentences

• Communities meet online via private Facebook groups.
• People no longer meet up in a community hall to discuss matters.
• Many people do not socialise physically with others.
• People like to isolate themselves in a virtual world. 

If you wrote all of your sentences like this in the essay, you would gain a low band score. Therefore, you take the basic sentences like those above and make them into complex sentences by joining them together. Take a look at the example below where you can see the word ‘since’ joins the sentences together;

Complex Sentence Example

Communities meet online via private Facebook groups, instead of in a community hall to discuss matters, since this does not allow them to socialise physically with people, they isolate themselves in this virtual world. 

Where do I use them in my essay?

In your writing task 2 essay, you can use a complex sentence in any part of the essay. Here we will look at how they can be used to explain your main idea in your main body paragraphs. Your first sentence can be a basic sentence, that introduces the main topic, followed by a complex sentence that explains the main idea, then an example, which can contain a mixture of simple and complex sentences. Think of it like this;

Main Body Paragraph

• Simple sentence (introduce your topic)
• Complex sentence (explain your topic/main idea)
• Complex sentence (example)

Take a look at this example below from a discussion essay;

Firstly, during the last two decades, there have been many tech developments and advancements, bringing convenience to all. One significant attribute of this modernization is the internet, while this technology has made our lives more convenient in many aspects, including our approach to communication. In the past, we only used mail or the telephone to send our messages across the globe, whereas today, the internet allows us to reach out to almost everyone in just a few seconds. The inconvenience of long distances is eliminated as we can talk and even see distant friends or relatives for an unlimited time. For example, the internet connects people whose relatives or families are abroad, through Facebook, Twitter or Skype anytime and anywhere.

If we break it up you can see how it has been structured;

The first sentence – introduces the topic and is simple >

Firstly, during the last two decades, there have been many tech developments and advancements, bringing convenience to all.

The second part of the paragraph is more complex and gives the reader an explanation of the main topic. The words highlighted in bold connect the clauses and make the sentences complex >

One significant attribute of this modernization is the internet, while this technology has made our lives more convenient in many aspects, including our approach to communication. In the past, we only used mail or the telephone to send our messages across the globe, whereas today, the internet allows us to reach out to almost everyone in just a few seconds. The inconvenience of long distances is eliminated as we can talk and even see distant friends or relatives for an unlimited time.

The third part of the paragraph is the example and it is a complex sentence, connected by the words highlighted in bold >

For example, the internet connects people whose relatives or families are abroad, through Facebook, Twitter or Skype in order to contact them anytime and anywhere.

Clauses – A clause is the key element of a sentence.

A clause is a group of words that contains a subject and a verb. It can form part of a sentence or a complete simple sentence. Clauses can be main or subordinate and they can behave like adjectives or adverbs.

Main Clauses – Also known as an independent clause, the main clause includes a subject and a verb and expresses a complete thought. Main clauses are the same as simple sentences because they have to make sense on their own. 

Example – The dog (subject) played (verb).

Subordinate Clauses – A subordinate clause (also called a dependent clause) contains a subject and a verb but it does not make sense on its own. It depends on the main clause for its meaning. Subordinate clauses often explain or add more information about where or when things happen, or how they are done. relative and adverbial clauses are types of subordinate clauses. 

Example – Because the dog (subject) was lazy (verb).

Relative Clauses – Relative clauses are also known as adjective clauses, and they are a type of subordinate clause. Like adjectives and adjectival phrases, relative clauses describe nouns and pronouns. Unlike adjectives, they can only be placed after the noun or pronoun they are modifying. Relative clauses always start with one of the relative pronouns who, whom, whose, which or that, which acts as the subject or the object of the clause.

Examples  

• Subject > which was (verb) excellent (adjective) 
• Object > which the dog (subject) did (verb) every day (adverbial phrase)

Adverbial Clauses – An adverbial clause is a type of subordinate clause that behaves like an adverb. It gives additional information about how, when where and why something is happening. Adverbial clauses start with subordinators such as because, although, after, while, as and until.

Examples

• Why? as (subordinator) the dog (subject) wanted (verb) food (object)
• When? after (subordinator) the dog (subject) had eaten (verb) food (object)

Sentence Structures

Simple Sentences

A simple sentence is the same as the main clause. it must have a subject and one main verb and it must express a single idea. The subject is the person or thing that does the action (the verb), but one subject can be made up of more than one person or thing. Most simple sentences also include an object, which is the person or thing receiving the action. 

Example

The student and his friends enjoyed the library field trip.

Compound Sentences

Compound sentences are made up of two or more main clauses, but no subordinate clauses. The main clauses are linked using conjunctions and the resulting sentence conveys different ideas of equal importance. Compound sentences are a useful way of connecting two or more ideas of equal importance. They help to improve the flow of a piece of writing as many successive simple sentences can be uncomfortable to read. to make most compound sentences, two main clauses, each containing a subject and a verb are joined together using a coordinating conjunction such as and, but or so. A comma is used before the coordinating conjunction to separate the two clauses.

Example

John is a student who loves to study English grammar, and he also reads many science fiction books. 

Complex Sentences

A complex sentence is made up of a main clause and one or more subordinate clauses. The subordinate clause depends on the main clause for its meaning. Complex sentences are useful because they can be used to indicate that one idea is more important than another. The secondary idea is contained in a subordinate clause, which has a subject and a verb but does not make sense without the main clause to which it is attached. Subordinate clauses add information to main clauses. 

Examples

John put his hat on because he was cold.

The couple allowed their dog to sleep on their bed, although they managed to have very little sleep.

Preparing For Your IELTS Test

Please practice writing IELTS essays and using complex sentences in your work before your test day. Some students try to write complex sentences, which then turn into very hard to understand sentences. They somehow get the word order muddled up and the writing becomes confusing. Don’t allow this to happen, check your work and practice, using essay examples to guide you. 

Even better – have lessons or essay corrections with an experienced teacher, who can help you to understand how to structure your essay, make it clear and include all of the necessary elements to pass with a high band score. 

We hope you found this post useful in helping you to study for the IELTS Test. If you have any questions please let us know in the comments below or on the Facebook page.

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