In IELTS Writing Task 2, grammar is not tested in isolation. Instead, examiners evaluate how effectively you use grammar to express ideas clearly and logically. One of the strongest indicators of a high-band essay is the controlled use of different sentence types, especially:
- Complex sentences
- Compound sentences
- Compound-complex sentences
Understanding these structures deeply—and using them correctly—can significantly improve your Grammatical Range and Accuracy score.
Why Sentence Structure Is Critical in IELTS Task 2
IELTS examiners assess grammar based on:
- Range → variety of sentence structures
- Accuracy → correctness and control
- Flexibility → ability to express relationships between ideas
Band Expectations (Simplified)
- Band 5–6 → mostly simple sentences, limited variety
- Band 7 → frequent complex sentences with good control
- Band 8–9 → wide range including compound-complex sentences used naturally
👉 Writing long sentences alone does not increase your band.
👉 Writing clear, logically structured sentences does.
Understanding the Building Blocks First
Before discussing sentence types, you must understand clauses.
Independent Clause (Standalone Clause)
- Has subject + verb
- Expresses a complete idea
- Can stand alone as a sentence
Example:
Governments should invest in education.
Dependent Clause (Non-Standalone Clause)
- Has subject + verb
- Starts with words like because, although, if, when
- Cannot stand alone
Example:
because education improves employment opportunities
1. Complex Sentences (Most Important for IELTS)
What Is a Complex Sentence?
A complex sentence contains:
- One independent clause
- One or more dependent clauses
These clauses are joined using subordinating conjunctions.
Common Subordinating Conjunctions in IELTS
| Purpose | Words |
|---|---|
| Cause | because, since, as |
| Contrast | although, though, whereas, while |
| Condition | if, unless, provided that |
| Time | when, whenever, after, before |
| Result | so that, such that |
Structure of a Complex Sentence
There are two correct positions:
1️⃣ Dependent clause first
Although public transport is affordable, many people prefer private vehicles.
2️⃣ Independent clause first
Many people prefer private vehicles although public transport is affordable.
(Both are correct. Comma usage matters.)
IELTS Examples with Explanation
Cause
Many students struggle in IELTS writing because they do not practise essay structures.
- Main idea: students struggle
- Reason: lack of practice
Contrast
Although online education is convenient, traditional classrooms remain popular.
- Expected outcome: online learning preferred
- Reality: classrooms still popular
Condition
If governments reduce tuition fees, higher education will become more accessible.
-
Condition → result logic
Why Complex Sentences Are Essential for Band 7+
- Show reasoning
- Connect ideas logically
- Avoid robotic writing
- Match academic tone
📌 At least 40% of your Task 2 sentences should be complex
2. Compound Sentences (Clarity & Balance)
What Is a Compound Sentence?
A compound sentence joins:
- Two independent clauses
- Using a coordinating conjunction
Coordinating Conjunctions (FANBOYS)
| Letter | Word |
|---|---|
| F | for |
| A | and |
| N | nor |
| B | but |
| O | or |
| Y | yet |
| S | so |
Structure
Independent clause, conjunction independent clause.
IELTS Examples
Contrast
Public transport is cost-effective, but many commuters still use private cars.
Result
Governments face budget constraints, so public services often suffer.
When to Use Compound Sentences
- When both ideas are equally important
- To show balance, contrast, or result
- To avoid overusing complex sentences
📌 Do not start every sentence with “and” or “but”.
3. Compound-Complex Sentences (Advanced / Band 8–9)
What Is a Compound-Complex Sentence?
It combines:
- Two independent clauses
- At least one dependent clause
This structure shows high grammatical control.
Structure Example
Although technology improves efficiency, many workers fear automation, and job insecurity is increasing.
IELTS Examples
Example 1
Although renewable energy is expensive initially, it reduces long-term costs, and it protects the environment.
Example 2
If children are encouraged to read regularly, their vocabulary improves, and their academic confidence increases.
How Many Should You Use?
- 1–2 per essay is enough
- Clarity is more important than complexity
- Avoid very long sentences with 3–4 clauses
📌 Overuse can reduce accuracy → lower band.
Common IELTS Grammar Mistakes to Avoid
❌ Sentence fragments
Because pollution is increasing. ❌
✔️ Corrected
Pollution is increasing because industrial emissions are rising.
❌ Incorrect comma usage
Although traffic is heavy many people drive cars. ❌
✔️ Corrected
Although traffic is heavy, many people drive cars.
❌ Overly long sentences
- Examiner loses clarity
- Accuracy drops
Ideal Sentence Mix for IELTS Task 2
| Sentence Type | Percentage |
|---|---|
| Simple | 25–30% |
| Complex | 40–45% |
| Compound | 15–20% |
| Compound-Complex | 5–10% |
This balance sounds natural and academic.
Examiner’s Perspective (Very Important)
Examiners do not count grammar rules.
They ask:
- Is the meaning clear?
- Are ideas logically connected?
- Does the candidate show control?
Even one well-used complex sentence is better than five incorrect advanced ones.
Final IELTS Writing Advice
Use grammar to support your ideas, not to show off.
Think first:
- What am I explaining? (cause, contrast, condition)
- Which sentence structure fits best?
Then write confidently.