Sentence Structures
This page about sentence structure will focus on the differences between simple sentences,
compound sentences, complex sentences and compound-complex sentences.
You must know how to correctly write these sentence types for IELTS as the examiner will be looking
for them when they grade you for your 'grammatical range'.
Sentence Types
There are four types of sentence:
Simple
Compound
Complex
Compound-Complex
1. Simple Sentences
A simple sentence is one clause with a subject and verb:
SV - Computers are important in the modern world.
However, it can have more than one subject and verb:
SSV - Computers and other technological devices are important in the modern world.
SVV - I search for information and play games on my computer.
SSVV - My brother and I search for information and play games on our computers.
2. Compound Sentences
A compound sentence consists of 2 or 3 clauses. It is when simple sentences are joined together.
In this sentence structure, the clauses are joined with the following coordinating conjunctions:
F = for
A = and
N = nor
B = but
O = or
Y = yet
S = so
The word 'fanboys' is an easy way to remember the different conjunctions that make up compound
sentences. Obviously the most common are 'and', 'but', 'or' and ‘so'.
Here are some examples of compound sentence structure:
SV but SV - Computers are important, but they can be dangerous too.
SV but SV so SV - Computers are important, but they can be dangerous too, so we must be careful.
Avoid writing too many clauses as the sentence may get difficult to follow, and you cannot use each
one more than once in a sentence to join clauses.
This is wrong:
X SV and SV and SV - Computers are used widely in most countries now, and they are a sign of
progress, and we must ensure everyone has access to them.
Two possible corrected versions:
SV and SV. SV. - Computers are used widely in most countries now, and they are a sign of
progress. We must ensure everyones has access to them.
or
SV and SV so SV. - Computers are used widely in most countries now, and they are a sign of
Using semicolons
There is an instance when you can have a compound sentence structure without a coordinating
conjunction, and this is when you join two clauses with a semicolon. It is used when two ideas are
related.
For example:
Computers are used widely in most countries; they are a sign of progress.
3. Complex Sentences
Complex sentences are more complicated (which is maybe why they are called 'complex'!).
This type of sentence structure is important for IELTS because to get awarded a band 6 or higher for
your 'grammatical range and accuracy', you need to demonstrate that you are able to use them.
The more varied and the more accurate your complex sentences are, the higher the band score for
this.
There are different types of complex sentences and these will be looked at in more detail later, so
here you are just provided with the basics.
Complex sentences are two (or more) clauses joined together, but they are not joined by
'fanboys' (coordinating conjunctions). They are joined by subordinating conjunctions.
These are subordinating conjunctions:
after
although
as
as if
as long as
as much as
as soon as
as though
because
before
even if
even though
if
in order to
in case
once
since
so that
that
though
unless
until
when
whenever
whereas
where
wherever
while
For example:
People take natural health supplements even though they may not have been tested.
Our children may not be properly educated if we don't spend more on schools.
I went to bed as soon as he left because I was tired.
These are all adverbial clauses. In these types of complex sentences, the second clause can be
used to start the sentence.
In this case, a comma is needed in the middle:
Even though they may not have been tested, people take natural health supplements.
If we don't spend more on schools, our children may not be properly educated.
As soon as he left, I went to bed because I was tired.
Noun clauses and relative clauses are also a type of complex sentence structure, but these will be
looked at later.
4. Compound-Complex Sentences
Compound-complex sentences are the same as complex sentences but they also have a simple (or
compound) sentence before or after the 'complex' part.
For example:
I ate a lot when I got home, but I was still hungry.
The part that is underlined is the complex sentence. As you can see, it also has a simple sentences
connected to it. It can also have a full compound sentence attached to it:
I ate a lot when I got home, but I was still hungry, so I went shopping to buy some more food.
Rules for Adverbial Clauses
Remember that adverbial clauses are made up of two clauses - an independent clause and
a dependent clause (look at these lessons on sentence clauses and complex sentences again if you
are not sure what clauses are).
1) Switching the Clauses
The first thing to note is that the independent and dependent clauses can be switched around:
After I have finished studying, I intend to work abroad.
(Dependent Clause + Independent Clause)
I intend to work abroad after I have finished studying.
(Independent Clause + Dependent Clause)
In all of the sentences in the table above, the clauses can be switched around.
2) Commas
Note though that if you switch them around and put the dependent clause first, a comma
must come at the end of the dependent clause:
After I have finished studying, I intend to work abroad.
(Comma)
I intend to work abroad after I have finished studying.
(No Comma)
This might seem like a minor point but it is quite important in your writing. Complex sentences can
sometimes get confusing if commas are missing as it can become unclear where one clause ends
and the other begins.
If any of your sentences are confusing, this will definitely reduce your score.
*'While' and 'Whereas' are exceptions to this rule because they do have commas even when they
appear in the middle of the sentence.
3) Meanings
Even though certain adverbs have been grouped together in the adverbial clauses table, this does not
mean that they are all synonyms for each other.
Some you can interchange with each other without changing the meaning. For instance, 'since', 'as'
and 'because' all have the same meaning and you can choose which one you want to use. But some
you cannot.
For example, look at these conditional adverbs:
I will go if you go.
I will go unless you go.
The word 'unless' does not work in the second sentence. It has to be changed:
I won't go unless you go.
Now it has the same meaning.
Similarly, 'although', 'even though', and 'though' are all synonyms of each other and can be
interchanged, but 'while' and 'whereas' cannot always be swapped with them.
So you need to practice each individual word and check how it is used.
A Common Mistake
A common mistake with adverbial clauses (and other complex sentences) is to write fragments.
A fragment is an incomplete sentence:
My English is not improving. Because I am not studying enough.
A dependent clause (the second one in this case) cannot be a sentence on its own. By placing a
full-stop after "improving", this has turned the second clause into a sentence fragment.
A dependent clause must have an independent clause attached to it:
My English is not improving because I am not studying enough.
When you check your work, you should check your complex sentences and check that you have not
written any fragments.
Examples in Context
Look at this sample essay. The adverbial clauses are coloured, with the independent clauses in green
(and italics) and the dependent clauses in red (and underlined). The adverbs are shaded in yellow.
Some people believe the aim of university education is to help graduates get better jobs.
Others believe there are much wider benefits of university education for both individuals and
society.
Discuss both views and give your opinion.
These days, more and more people are making the choice to go to university. While some people are
of the opinion that the only purpose of a university education is to improve job prospects, others
think that society and the individual benefit in much broader ways.
It is certainly true that one of the main aims of university is to secure a better job. The majority of
people want to improve their future career prospects and attending university is one of the best
ways to do this as it increases a persons marketable skills and attractiveness to potential
employers. In addition, further education is very expensive, so most people would not consider
it if it would not provide them with a more secure future and a higher standard of living. Thus job
prospects are very important.
However, there are other benefits for individuals and society. Firstly, the independence of living
away from home is a benefit because it helps the students develop better social skills and improve
as a person. A case in point is that many students will have to leave their families, live in halls of
residence and meet new friends. As a result, their maturity and confidence will grow enabling them to
live more fulfilling lives. Secondly, society will gain from the contribution that the graduates can make
to the economy. We are living in a very competitive world, so countries need educated people in
order tocompete and prosper.
Therefore, I believe that although a main aim of university education is to get the best job, there are
clearly further benefits. If we continue to promote and encourage university attendance, it will lead
to a better future for individuals and society.
It is good to have a variety of sentences types. And as you can see, there are a mix of adverbial
clauses which demonstrates that the candidate has a good grammatical range.
Try writing your own essay. When you have finished, go through your work and highlight the adverbial
clauses, identifying the adverb and the dependent and independent clauses.
Is there a mix? Are they used correctly with subjects and verbs present in each clause and no
fragments?
Relative Clauses
Relative clauses are a type of complex sentence.
It essential that you know how to write complex sentences if you want to do well in the IELTS writing
test.
Here are some examples used in an IELTS task 1:
Consumption of pizzas was far higher than hamburgers, which were consumed approximately 5
times a year.
Community contributions, which were the second largest revenue source, brought in 10.4% of
overall income, and this was followed by program revenue, at 2.2%.
Here are some examples from task 2 essays:
CO2, which damages the ozone layer, comes from several sources, but the most problematic are
those coming from the burning of fossil fuels from power plants.
Email and social networking sites such as Facebook and MSN have created online communities that
are global in scale.
Relative clauses can refer to:
People = who / that
Things = which / that
Places = where
Below are some essential rules about these types of clauses that you must know.
The rules refer to independent and dependent clauses, so make sure you understand these first.
8 things you must know about relative clauses:
1) Relative clauses modify nouns, and they must come after the noun they are modifying:
noun
relative clause
The car, which is my father’s, is in the garage.
noun
relative clause
The car is in the garage, which is locked.
In the first sentence, the relative clause is referring to "the car", so it comes after that noun. In the
second sentence it is referring to "the garage".
__________________________________________________
2) There must be an independent and dependent clause:
Ind Clause
Dep Clause
Ind Clause
The car, / which is my father’s, / is in the garage.
__________________________________________________
3) As there are two clauses, there must be a subject and verb in each:
S
S V
V
The car, / which is my father’s, / is in the garage.
This is because a relative clause is two simple sentences joined together. In other words:
S
V
The car is in the garage.
S
V
The car is my fathers.
__________________________________________________
4) If you miss part of one of the clauses out, or one of the subjects or verbs, you will create
a fragment (an incomplete sentence):
S
S V
The car / which is my father’s.
This is incorrect as there must be a full dependent and independent clause.
__________________________________________________
5) The verb in the relative clause must agree (i.e. singular subject takes singular verb) with the noun it
is modifying:
Subj (sing)
verb (sing)
The car, / which is my father’s, / is in the garage.
__________________________________________________
6) If the information is ‘extra’ information, there are commas:
The car, which is my father’s, is in the garage.
The relative clause is not identifying the noun, it is just extra information about who owns it.
__________________________________________________
7) If the information is ‘essential’, there are no commas:
The car which is in front of the house is mine.
This is identifying which car, so it is essential. There are probably other cars, so without the relative
clause we will not know which car is being talked about.
In other words, if you said "the car is mine", this would not help us. Which car?
__________________________________________________
8) With ‘essential’ relative clauses, ‘that’ can replace ‘who’ or ‘which’:
The car that is in front of the house is mine.
The police have not found the person that stole my car.
Noun Clauses
A Noun clause is another type of complex sentence that you are likely to use when you do any form
of writing or speaking, so you need to be aware of them for IELTS.
And remember that to score at a band 6 or above for the grammatical range and accuracy criteria
in the IELTS writing marking, you must show that you are able to use complex sentences with at least
some accuracy.
For a band 6 you may still make some errors with them, but errors are a lot less likely for someone
scoring a band 7 or higher.
This of course does not mean you have to them in your writing! There are lots of other types of
complex sentence, but it is likely you will use some.
For your speaking too, you need to be able to use a mix of complex structures with some flexibility.
What is a Noun Clause?
If you don't know what a noun or a noun phrase is, you should check these out before you continue
with this lesson.
This is a noun clause definition:
A group of words (which do what a noun does) with a subject and a verb that can be a subject, an
object, or an object of a preposition.
Here are 4 common types of noun clauses (NC):
1.
2.
3.
4.
Subject NC
Direct Object NC
Object of Preposition NC
Subject as Complement NC
It is a dependent clause which means it must also have an independent clause, but we will look at
this further when we analyse each type.
Before we look at these in turn, let's look at how this type of clause begins.
Starting the Clause
They start with a relative or adverb pronoun. These are the words that commonly commence such a
clause:
where
why
if
that
when
whether
who
whom
which
what
how
how (adj)
- "ever" words
wherever
whomever
whenever
whatever
whichever
whoever
however
however (adj)
Types of Clauses
Now we'll look at the different types. Before we do this, take a look at these noun clause examples
(the whole clause is in bold and the relative or adverb pronoun is in red). Each different type is shown:
Subject NC
How governments are fighting global warming is being scrutinised by the media.
Direct Object NC
Most people believe that obesity cannot be reduced just by reducing calorie intake.
Object of Preposition NC
He talked with whichever person arrived first.
Subject as complement NC
It is important that the individuals do everything they can to help educate their children.
1. Subject Noun Clauses
For these explanations, the subjects will be in green, the verbs in blue, and the objects in red.
In this type of sentence the NC (underlined) is the subject of the sentence:
What causes so many difficulties in the IELTS test is the writing section.
So looking at the whole sentence above, we have a subject, a verb and an object.
But remember that a NC is a 'clause', so it too must have a subject and a verb (and possibly an
object):
What causes so many difficulties in the IELTS test is the writing section.
In the above example, the adverb pronoun ("what") is the subject. It does not have to be as in this
example, where "I" is the subject:
Whether I go or not is up to me.
Important: Note that the verb "is" is singular. A NC is counted as a singular subject, so it takes a
singular verb.
You can learn more about subject verb agreement here.
2. Direct Object Noun Clauses
When the clause is the direct object, then it comes after the verb in the independent clause:
This history book describes how England became the first industrialised nation.
Again, remember that the NC has a subject and a verb (and possibly an object):
This history book describes how England became the first industrialised nation.
A common NC you will know from IELTS is the "that" clause, following verbs such as "think",
"believe" and "feel", for example as in this Task 2 essay question:
A growing number of people feel that animals should not be exploited by people and that they should
have the same rights as humans, while others argue that humans must employ animals to satisfy their
various needs, including uses for food and research.
Discuss both views and give your opinion.
And you may then give your opinion:
Personally, I do not believe that it is necessary to exploit animals for our own satisfaction.
Note that if you are speaking it is fine to leave "that" out of the sentence (this is then a reduced noun
clause).
I believe students should not have to wear a uniform.
But for formal writing such as you do in IELTS you should keep the "that" in the sentence.
I believe that students should not have to wear a uniform.
3. Object of the Preposition Noun Clauses
In this case, the NC comes after a preposition:
My Aunt is very chatty. She speaks to whoever will listen!
And here it is with the subject and verb of the NC highlighted:
My Aunt is very chatty. She speaks to whoever will listen!
4. Subject as Complement Noun Clauses
These type of sentences have the following structure:
It + be + adjective + (NOUN CLAUSE: that + S + V)
It is important that the government tackles obesity.
It is essential that children have enough leisure time.