Grammatical Range and Accuracy accounts for 25% of your IELTS Writing and Speaking scores. To reach Band 7, you must demonstrate 'a variety of complex structures'. Complex sentences — those containing a main clause and one or more subordinate clauses — are the primary vehicle for demonstrating this range. This guide explains the most useful complex sentence structures for IELTS and how to use them accurately.
1What Makes a Sentence 'Complex'?
A simple sentence has one main clause: 'Technology has changed society.' A compound sentence has two main clauses joined by a coordinating conjunction: 'Technology has changed society, and this transformation continues to accelerate.' A complex sentence has one main clause and one or more subordinate clauses: 'Although technology has undoubtedly improved living standards, its social consequences remain a subject of significant debate.' The subordinate clause ('Although technology has undoubtedly improved living standards') cannot stand alone — it depends on the main clause for its meaning. Examiners look for a mix of simple, compound, and complex sentences. Relying entirely on one type limits your Grammatical Range score.
2Most Useful Subordinating Conjunctions for IELTS
Concession (showing contrast): although, even though, while, whereas, despite the fact that. Example: 'While urbanisation has brought economic benefits, it has simultaneously intensified social inequality.' Cause and effect: because, since, as, given that, due to the fact that. Example: 'Since water scarcity is expected to worsen with climate change, investment in water management infrastructure has become critically urgent.' Condition: if, unless, provided that, as long as, on condition that. Example: 'Provided that governments invest adequately in public education, the long-term economic returns far exceed the initial costs.' Time: when, while, as soon as, by the time, once. Example: 'Once artificial intelligence systems become sufficiently sophisticated, their implications for the workforce will require comprehensive policy responses.'
3Relative Clauses: Adding Detail Without New Sentences
Relative clauses are subordinate clauses that modify a noun, using relative pronouns: who (people), which (things), that (people or things), whose (possession), where (places), when (times). Defining relative clause (no commas — essential to meaning): 'The policy that the government introduced last year has proved controversial.' Non-defining relative clause (commas — additional information): 'The policy, which was introduced despite significant opposition, has since been partially reversed.' Non-defining relative clauses demonstrate sophisticated grammar because they add information economically within one sentence rather than across two. They also require correct comma placement — a sign of grammatical accuracy.
4Common Errors to Avoid
Error 1 — Comma splice: Two main clauses joined with a comma only: 'Technology benefits society, it also creates problems.' Fix: add a coordinating conjunction ('but') or create a complex sentence using 'although'. Error 2 — Dangling modifier: 'Having studied the issue carefully, the government's response was disappointing.' The government did not study the issue. Fix: 'Having studied the issue carefully, researchers found the government's response disappointing.' Error 3 — Tense inconsistency in complex sentences: 'Although the economy grows, wages had not kept pace.' Fix: align tenses — 'Although the economy has grown, wages have not kept pace.' Error 4 — Missing comma after initial subordinate clause: 'Although technology brings benefits people should remain critical.' Fix: 'Although technology brings benefits, people should remain critical.'
🎯 Key Takeaway
Complex sentences are not about showing off — they are about expressing complex ideas concisely and precisely. Each IELTS Writing Task 2 paragraph should contain at least one complex sentence. In Speaking, each Part 3 answer should include complex structures naturally. Practise by converting three simple sentences per day into complex ones using the structures above.