Complex Sentences

On this page, we will learn about complex sentences, Why are complex sentences important for the ielts exam? The marking criteria, What are independent and dependent clauses? What are the types of complex sentences? What are adverbial clauses?, what are relative clauses?, what are noun clauses?, and how can I improve the IELTS band with complex sentences?

What is complex sentences?

A complex sentence is a sentence that consists of an independent clause (a complete sentence) and one or more dependent clauses (subordinate clauses) connected by subordinating conjunctions or relative pronouns.

Here's an example of a complex sentence:

"While I was studying for my exams, my sister was watching TV."

N:B: If subordinate clause comes first, give a ( , ) comma before independent clause

Explanation: In this sentence, "While I was studying for my exams" is a dependent clause because it cannot stand alone as a complete thought. The independent clause is "my sister was watching TV," which can function as a complete sentence on its own.

Why complex sentences is important for ielts exam?

In the IELTS exam, using complex sentences is crucial for demonstrating advanced language proficiency, showcasing a variety of sentence structures, expressing complex ideas effectively, and contributing to higher scores in writing, coherence, and cohesion. It is an essential skill across all test sections, indicating a sophisticated use of English that positively impacts overall band scores. If you are unable to write them or have a very limited ability to write them, the examiner will not give you a band higher than 5 for your "grammatical range and accuracy".

What are the types of complex sentence?

Complex sentences have three types:

  1. Adverbial Clauses
  2. Relative Clauses
  3. Noun Clauses

The construction of each of them is briefly explained in the sections that follow, along with some examples.

What is adverbial clauses?

Adverbial clauses provide answers to queries like "how?" why? When? Where?

They are created by using a subordinating conjunction to join an independent clause and a dependent clause.

These typical subordinating conjunctions that create complex phrases are listed below:

because although if untill
while when even though as

For example (the subject is in green and the verb in blue):

He didn't get an ice-cream after dinner, because he didn't finish his homework properly.

SV subordinating conjunction SV

He didn't get an ice-cream after dinner


because he didn't finish his homework properly.


The dependent clause can, however, come before the independent clause in adverbial clauses. In actuality, this is the case the majority of the time.

The dependent clause MUST be followed by a comma in this case (a comma is not required when the independent clause comes first):

Because he didn't finish his homework properly, he didn't get an ice-cream after dinner.

Subordinating conjunction SV, SV

Here are a few more instances. Take note of how the dependent clause appears first in some sentences while coming second in others. You have the option to:

Even though he arrived late, he was misbehaving with others.

Air pollution will get worse if factories emissions are not reduced.

While the number of travellers visiting Japan increased, the number visiting the UK decreased.

I can't assume when he will take-off.

Although he is poor, he is honest.

I'll stay here until you come back.

What is relative clauses?

Relative clauses contain an independent clause and a dependent clause, just like adverbial clauses do.

These clauses, however, have a distinct purpose. A noun is modified by relative clauses. To clarify, to provide more details about it.

This is accomplished by using the relative pronouns who, which, that and where, and by placing the relative clause following the noun it is modifying.

For example:

My cousin, who just shifted here, is coming to lunch with us.

My cousin is coming to lunch with us.


who just shifted here


In contrast to adverbial clauses, the dependent clause—also known as the relative clause—can split the independent sentence; it only needs to come after the noun, wherever it may be.

Notably, there are two different Subject-Verb pairs. Given that there are two clauses, this will always be the case for complex sentences.

Here are a few more instances. The independent clause is bold, the independent clause is underlined, and the dependent (relative) clause is highlighted in blue.

A library is such a place where you can't make any noise.

Greenhouse effect is a big problem that must be solved.

Obesity, which is the state of being overweight , affects millions of children worldwide.

A person who follows the law must get appreciations.

What is noun clauses?

Since noun clauses are arguably the most challenging to understand among complex sentences, we'll concentrate on the most typical and straightforward form, which you've probably used numerous times. Later, we'll take a closer look at them.

The query "who?" or "what?" is answered by a noun phrase. Noun clauses follow the verb, as opposed to relative clauses, which follow the noun.

For example:

What is your opinion about child-labor?

I think that child-labor is wrong and that those guilty of it should be punished.

In this illustration, the verb "think" has two noun phrases as its objects.

Because they are incomprehensible on their own, the noun clauses are the dependent clauses. The independent sentence "I think..." is required.

I think


that child-labor is wrong that those guilty of it should be punished


Here are a few more instances. The independent clause is bold and the dependent (noun) clause is highlighted in blue:

I concur that the death penalty must be eliminated.

I hope that the government steps in to make things right.

I believe that the experimentation on animals is wicked.

When speaking, it's typical to omit the word "that." For instance, we could say:

I believe experimentation on animals is wicked.

However, you should include it in official writing, like IELTS, or academic writing in general.

Additional guidelines and options for using these adverbial, relative, and noun clauses exist, but we shall examine them in more depth later.

You will learn the fundamentals of their usage in this lesson.

How to improve IELTS band by Complex Sentences?

You would need to be able to employ a variety of these complex sentences accurately for a band 6 or higher, and extremely accurately for a band 7 or above, in order to receive a satisfactory grade for your grammatical range.

You should also aim to use these structures in more complicated ways for bands 7 and higher, for as by minimizing your use of relative clauses and using nominalizations.