Complex sentences

A complex sentence is any sentence in which one clause is grammatically subordinate to another. That is the entire definition — a nine-word sentence with one because-clause is complex; a forty-word sentence full of rare vocabulary but only one clause is not.

The band descriptors turn on this distinction. Band 6 speaking is 'a mix of simple and complex structures, but with limited flexibility'; Band 7 is 'a range of complex structures with some flexibility' and 'frequently produces error-free sentences'. Since Grammatical Range and Accuracy is a quarter of your mark in both Speaking and Writing, subordination — done accurately — is the highest-value grammar habit you can build.

• If rents keep rising, key workers will leave the city.(a conditional — a complex sentence examiners credit)
• The scheme failed because nobody promoted it.(one subordinator is enough — this counts)
• Utilisation of infrastructural amenities remains suboptimal.(hard vocabulary in a one-clause sentence is not grammatical complexity)

Five families cover almost every idea an IELTS answer needs: reason (because, since, as), concession (although, even though, whereas, while), condition (if, unless), time (when, after, before, until), and purpose (so that). Add the relative pronouns who and which and you have a complete toolkit.

Concession is the highest-value family. Discussion essays and Part 3 questions constantly ask you to weigh two sides, and although lets you hold both in a single sentence — acknowledging one view while committing to the other. That is precisely the evaluative thinking the test is designed to reward.

• Whereas older residents prefer the market, teenagers shop online.(whereas contrasts two clauses in one sentence)
• Unless the ministry funds training, the reform will stall.(unless = if not)
• The festival was postponed until the smoke cleared.(time clause in end position — no comma)

The rule is positional. A subordinate clause before the main clause is followed by a comma; a subordinate clause after the main clause usually takes none. Contrast clauses with although or whereas often keep a comma even in end position, because the contrast reads as an afterthought.

Non-defining relative clauses are the other comma case: a which-clause adding extra information sits between commas. Master these two habits and the punctuation half of 'good control of grammar and punctuation' — the Band 7 writing phrase — is largely solved.

• After the internship ended, Amara stayed on as a consultant.(comma after the fronted clause)
• Amara stayed in Accra because the firm offered her a contract.(no comma before because here)
• Because the deadline moved we cancelled the workshop.(fronted clause needs a comma → Because the deadline moved, we cancelled the workshop.)

Complexity only pays when it stays accurate. The Band 5 writing descriptor is blunt: candidates at that level 'attempt complex sentences but these tend to be less accurate than simple sentences'. Ambition without control does not push your score up — it holds it down, because every broken structure feeds your error density.

The 6-to-7 jump is therefore not about adding more subordinators; it is about accuracy inside the ones you already use. A reliable rule: one subordinate idea per sentence. If a draft sentence holds three clauses and you can feel the grammar wobbling, split it. An accurate simple sentence always beats a broken complex one — but note the floor as well: at Band 4, 'subordinate structures are rare', so avoiding subordination entirely is just as costly.

• Although remote learning expanded access, it widened the gap for families without reliable internet.(one main idea, one subordinate idea — Band 7 material)
• Although many people is thinking that the technology which changing our lifes rapidly are good, but I am not agree.(stacked clauses with agreement errors — ambition without control)
• Traffic jams waste fuel. They also raise stress levels.(accurate simple sentences are fine — just add subordination elsewhere)

Spoken complexity is lighter than written complexity. Native speakers subordinate constantly, but in short clauses of five to eight words: a quick because here, an if-clause there. Nobody speaks in essay syntax, and trying to sounds rehearsed.

Build three or four flexible frames you can deploy without thinking: 'Although I see the appeal of X, I'd say…', 'If I had to choose, I'd probably…', 'What I like about it is that…'. These generate a subordinate clause in your first breath, then let you finish with ordinary words. Avoid memorising long templates — examiners are trained to spot recited language, and it costs you under Fluency.

• I usually cycle to work, although in winter I take the metro.(natural spoken concession)
• If I get the scholarship, I'll move to Melbourne in March.(a first conditional — instant, easy complexity)
• Notwithstanding the aforementioned considerations, I opine that city life is preferable.(grammatical, but memorised formal chunks sound rehearsed in speech)