IELTS Writing: Sentence Construction – an A-Z guide

Grammar is a crucial marking criterion not only in Writing but also Speaking. In particular, along with applying vocabulary in correct context, grammar is assessed on how you write a SENTENCE.  In the other words, the examiner will evaluate your ability to use a wide range of structure. You should bear in mind that a decent essay should include:

– Opening (2 sentences)
– Body (2 paragraphs with 5-6 sentences per paragraph)
– Conclusion (2 sentences)
Thus, a good essay only contains 14-16 sentences so if you write good sentences, you can create a decent paragraph. When you connect decent paragraphs you will get a fabulous essay. Very simple!

So the question is how to construct good sentences.

Simply, there are 3 types of sentences we can write, namely, SIMPLE SENTENCES, COMPOUND SENTENCES, and COMPLEX SENTENCES. Now, I will guide you how to write each type of sentences.


1- SIMPLE SENTENCES (lowest score)

– Sentence structure:

You can construct a simple sentence using these structures:

  1. S+V+O. (John likes cats)
  2. S+S+V+O. (John and Janet like cats)
  3. S+V+V+O. (John do not hate and do not have a cat)

In the other words, no matter whether how many subject, verbs, or objects you get in your sentence, it’s still a simple sentence. In fact, you cannot gain a high score by using this kind of sentence.

2- COMPOUND SENTENCES (higher score)

A compound sentence is created by connecting 2 simple sentences using FANBOYS (coordinators: for, and, nor, but, or, yet, so; remember to distinguish between BUT and YET) or TRANSITION WORDS (however, furthermore, moreover, in addition, etc.)

– Sentence structure:

S+V+O + (linking words) + S+V+O

– Example:

A nuclear plant requires strict safety controls, so staff is trained for nearly a year before its operation.

3- COMPLEX SENTENCES (highest score)

– Sentence structure:

S + V + O

in which: 

S or O contains one clause (clause = S+V+O)
For example:

The increasing number of private vehicles put more strain on public infrastructure that the Government has to reconstruct it annually.

S = The increasing number of private vehicles
V = put
O = more strain on public infrastructure / that the Government has to reconstruct it annually ( after “that” is a clause)

A complex sentence is popular with 3 kinds of clauses which are NOUN CLAUSES, ADJECTIVE CLAUSES, ADVERB CLAUSES.



Functions:  Act as a noun but it is a clause (S+V+O). Thus, it will stand at the position of Noun.

>If it acts as a Subject (S):
Whether the Government should ban private vehicles/ is / a controversial issue

• It / is / true that technology is increasingly discouraging human interactions (note that this sentence use  “it” as a dummy subject in the replacement for the group of words after “that…”). Actually, this sentence is: that technology is increasingly discouraging human interactions is true. However, in Academic writing, we should not use “that” at the beginning of a sentence so we should use “it” instead.

 >>If it acts as an Object (O):

• Some people / believe / that formal education is a guarantee for their future success.

• However, others / hold / an opposite opinion that early working experience brings young people more competitive advantages in the future.

>>Some excellent sentences: (What…not…but…)
• What young people need most is NOT money, BUT soft skills and working experience in some key areas
• What most companies need is NOT robots, BUT creative people who can contribute ideas.


Functions: Act as an adjective, or in the other words, this is a complement clause for a noun.

Students who rely on teachers for knowledge / are / passive in their learning.

Children who are over dependent on technology / may have / a tendency to accompany a sedentary lifestyle.

Working at home / is / suitable for employees that have their own working disciplines.

>>>, which (replacement for the whole sentence)
Manufacturers discharge chemical waste into the rivers, which deteriorates water-quality
(, which is a complement clause for the whole clause before it, this means “the act of discharging chemical waste into the rivers will deteriorate water quality”)


Functions: Act as an adverb, this clause talk about time (when), place (where), condition (if) – all condition clause is the complex sentence.

While many countries try to cut down on emissions, US Government withdraws from Paris Climate Agreement.

If a student wants to be successful in their future career, they need to learn about job-specific information.


You should bear in mind that in your essay, complex sentences must comprise at least 70% of total sentences to get the maximum score.
You can also connect a complex and a compound sentence to generate a more sophisticated complex sentence.

For example:
Upon graduation, some students wanted to travel, but others went to work.

After you finish writing, remember to finding some experts to correct your essay. If you cannot find one, we suggest you use Grammarly or click on the banner below to install. It’s free and very useful. Additionally, guidance on how to use it can be found at



The article was translated by our volunteer from Hai Vu – an IELTS teacher.



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1 Response

  1. June 21, 2017

    […] The guidance on how to construct a sentence can be found at IELTS Writing: Sentence Construction from A-Z guide. […]

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