IELTS Writing Grammar: Complex Sentences for Band 7+

Quick Answer: Complex sentences combine an independent clause with one or more dependent clauses using subordinating conjunctions (e.g., although, because, while) or relative pronouns (who, which, that). To reach Band 7+, you must use them accurately and flexibly, showing control over punctuation and clause structure. Simple sentences alone won’t score high.

Table of Contents

What Are Complex Sentences?

Why They Matter for Band 7+

Types of Complex Sentences for IELTS

Band Score Comparison Table

What Are Complex Sentences?

A complex sentence has one independent clause (a complete thought) and at least one dependent clause (an incomplete thought that cannot stand alone). The dependent clause is connected by a subordinating conjunction (e.g., although, because, while, since, unless) or a relative pronoun (e.g., who, which, that).

Example:

Simple: Pollution is harmful.

Complex: Although pollution is harmful, many industries still ignore regulations.

In the complex version, Although pollution is harmful is the dependent clause (it cannot stand alone), and many industries still ignore regulations is the independent clause.

Why They Matter for Band 7+

The IELTS Writing band descriptors for Task 2 (and Task 1) explicitly require:

Band 7: “Uses a variety of complex structures with some flexibility and accuracy.”

Band 8: “Uses a wide range of structures with full flexibility and accuracy; rare errors.”

Band 9: “Uses a wide range of structures with full flexibility and precision; no noticeable errors.”

If you only write simple or compound sentences (e.g., I went to the store, and I bought milk), you cannot score above Band 6 in Grammatical Range and Accuracy. Complex sentences show the examiner you can manipulate grammar to express nuanced ideas.

Types of Complex Sentences for IELTS

1. Subordinating Conjunctions (Adverbial Clauses)

These show relationships like time, reason, contrast, condition, or purpose.

Time: When the government implements stricter laws, pollution levels will drop.

Reason: Because renewable energy is cheaper, many countries are investing in it.

Contrast: Although urbanisation brings economic growth, it often leads to overcrowding.

Condition: If individuals reduce waste, the environment will benefit.

Purpose: Schools should teach financial literacy so that students can manage money wisely.

2. Relative Clauses (Adjective Clauses)

These add extra information about a noun using who, which, that, whose, where.

Defining (essential): Students who practice writing daily improve faster.

Non-defining (extra info, with commas): The internet, which connects billions of people, has transformed communication.

3. Noun Clauses

These act as a subject or object in a sentence.

Subject: What many people overlook is the impact of social media on mental health.

Object: Experts believe that climate change is accelerating.

4. Reduced Relative Clauses (Advanced)

Original: The man who is standing there is my teacher.

Reduced: The man standing there is my teacher.

5. Inversion (Formal/Writing)

Standard: Not only does exercise improve health, but it also boosts mood.

Inversion: Rarely do governments act quickly enough on environmental crises.

Band Score Comparison Table

Band	What Examiner Wants
6	Uses a mix of simple and complex sentences, but errors occur when attempting complex structures. Some subordination, but often awkward or incorrect punctuation.
7	Uses a variety of complex structures with some flexibility. Errors are rare and do not cause misunderstanding. Can use subordination and relative clauses accurately.
8	Uses a wide range of structures with full flexibility. Almost no errors. Can handle inversion, reduced clauses, and noun clauses naturally.
9	Uses all structures with precision and control. No noticeable errors. Complex ideas expressed elegantly without awkwardness.

Sample Answers

Band 7: Although many people believe technology improves education, it can also create distractions. For instance, students who use smartphones in class often lose focus, which hinders their learning. However, if teachers integrate technology effectively, it can enhance engagement. Band 8: While technology undoubtedly offers educational benefits, such as access to vast resources and interactive tools, it simultaneously poses challenges that require careful management. Students who lack self-discipline may find themselves distracted by social media, a problem that schools must address through clear policies. Moreover, because digital devices are ubiquitous, educators must adapt their methods to ensure that technology serves learning rather than undermining it. Band 9: Although technology has revolutionised education by democratising access to information, its integration into classrooms is not without pitfalls. Students who fail to develop self-regulation often succumb to digital distractions, a phenomenon that, if left unchecked, can erode academic outcomes. Nevertheless, when educators employ technology strategically—for instance, through gamified learning platforms or collaborative tools—it can foster deeper engagement and critical thinking. Ultimately, the extent to which technology benefits education depends on how effectively it is wielded by both teachers and learners.

Common Mistakes

❌Comma Splices with Subordinators: Although pollution is harmful, many industries ignore it. (Correct) vs. Although pollution is harmful, many industries ignore it, but they should act. (Incorrect: two independent clauses with ‘although’ + ‘but’).

❌Dangling Modifiers: Walking to school, the rain started. (Wrong: rain didn’t walk). Correct: While I was walking to school, the rain started.

❌Overusing the Same Structure: Because…, because…, because… Variety is key. Mix subordination with relative clauses and noun clauses.

❌Missing Commas in Non-Defining Relative Clauses: My brother who lives in London is a doctor. (Implies you have multiple brothers). Correct: My brother, who lives in London, is a doctor.

❌Incorrect Subject-Verb Agreement in Complex Sentences: The number of students who is studying abroad is rising. (Should be ‘are studying’ because ‘who’ refers to ‘students’).

Top Tips

💡 Tip 1: Use subordinating conjunctions to show logical relationships. Start sentences with Although, While, Because, Since, Unless to add depth.

💡 Tip 2: Combine relative clauses with subordination. Example: The policy, which was introduced last year, has reduced traffic congestion, although some residents oppose it.

💡 Tip 3: Avoid overcomplicating. One complex sentence per paragraph is better than a dense, error-filled sentence. Aim for 2–3 complex sentences in a 250-word essay.

💡 Tip 4: Practice reducing relative clauses. The person who is responsible for the project → The person responsible for the project. This shows advanced control.

💡 Tip 5: Read model essays aloud. Notice how complex sentences flow. Imitate the rhythm.

FAQ

Q: Can I use only complex sentences in my essay? A: No. Mix simple, compound, and complex sentences for natural flow. Overusing complex sentences can make your writing sound forced. Q: How many complex sentences should I aim for in Task 2? A: For Band 7+, aim for 4–6 complex sentences in a 250–300 word essay. Quality over quantity. Q: Is it okay to start a sentence with ‘Because’? A: Yes, but be careful. Because introduces a dependent clause, so the sentence must have an independent clause: Because pollution is rising, governments must act. Q: What’s the difference between ‘which’ and ‘that’? A: ‘That’ is used in defining (essential) clauses without commas. ‘Which’ can be used in non-defining (extra) clauses with commas. Example: The book that I read was good. (specific book) vs. The book, which I read, was good. (all books). Q: Do I lose marks for using simple sentences? A: No, but if you only use simple sentences, you cannot score above Band 6 for grammatical range.

Key Takeaways

✅Complex sentences combine an independent clause with a dependent clause using subordinators or relative pronouns.

✅Band 7+ requires variety, flexibility, and accuracy—not just one type.

✅Common mistakes include comma splices, dangling modifiers, and overuse.

✅Practice with subordinating conjunctions, relative clauses, and noun clauses.

✅Read sample answers and mimic their structure.

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IELTS Writing Task 2: How to Structure a Band 9 Essay

IELTS Grammar: Avoiding Common Errors

IELTS Writing Vocabulary: 10+ Words for Band 7+