GrammarJune 20, 2026 · 6 min read

IELTS Grammar: How to Write Complex Sentences That Score Band 7+

Complex sentences demonstrate grammatical range. Here's exactly how to write them correctly — with sentence structures, examples, and common errors to avoid.


Grammatical Range & Accuracy is 25% of your IELTS Writing score. To reach Band 7, the examiner must see "a variety of complex structures with some flexibility and accuracy." This means you need to use complex sentences — not just simple ones.

What Is a Complex Sentence?

A complex sentence contains a main clause (can stand alone) and one or more subordinate clauses (cannot stand alone). They are connected by subordinating conjunctions.

Simple: "Technology improves communication."

Complex: "Although technology has significantly improved communication, some argue that face-to-face interaction has suffered as a result."

The Most Useful Subordinating Conjunctions for IELTS

  • Concession: although, even though, while, whereas, despite the fact that
  • Cause/Reason: because, since, as, given that
  • Condition: if, unless, provided that, as long as
  • Purpose: so that, in order that
  • Time: when, while, before, after, once, as soon as

Relative Clauses

Relative clauses are another key structure for grammatical range. They add information about a noun using who, which, that, where, or whose.

Defining: "Students who study consistently tend to achieve higher band scores."

Non-defining: "IELTS, which is accepted by over 10,000 organisations worldwide, is the world's most popular English proficiency test."

Non-defining relative clauses (with commas) are particularly valued in Band 7+ writing.

Participial Phrases

Participial phrases are an advanced structure that shows high grammatical range:

Present participle: "Having considered both sides of the argument, I believe that..." (instead of "I have considered both sides, so I believe that...")

Past participle: "Built in the 19th century, the bridge remains one of the city's most important landmarks."

Common Errors

  • Comma splice: "Technology helps communication, it connects people globally." (Should be: "...communication because it connects...")
  • Dangling modifier: "Having studied English for years, the test was easy." (Who studied? The sentence implies "the test" studied.)
  • Overlong sentences: Adding 5 clauses to one sentence causes confusion. Two or three is usually the maximum.

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