Complex Sentences Without the Confusion

IELTS rewards "complex sentences." But many test-takers think complex means long and complicated. That's wrong. A complex sentence combines ideas clearly using conjunctions and relative clauses. Here's how to do it right.

What Is a Complex Sentence?

A complex sentence has one independent clause (a complete thought) and at least one dependent clause (incomplete without the main clause).

Simple: Traffic congestion is a problem. It affects productivity.

Complex: Traffic congestion, which affects productivity, is a growing problem in cities.

The second sentence combines both ideas smoothly.

Method 1: Relative Clauses

Use "which," "who," or "that" to add extra information about a noun.

Which (for things)

Two sentences: Solar energy is renewable. It produces no emissions.

Combined: Solar energy, which produces no emissions, is renewable.

Who (for people)

Two sentences: Students study abroad. They gain international experience.

Combined: Students who study abroad gain international experience.

That (for things or people)

Two sentences: Companies invest in training. They see higher employee retention.

Combined: Companies that invest in training see higher employee retention.

Comma Rules

Use commas with "which" when adding extra information.

Don't use commas with "that" or "who" when identifying which specific person or thing.

Method 2: Subordinating Conjunctions

These words show relationships between ideas:

Because, Since, As (reason)

Two sentences: Oil prices rose. Companies reduced production.

Combined: Companies reduced production because oil prices rose.

Although, While, Even though (contrast)

Two sentences: Electric cars are expensive. Sales are increasing.

Combined: Although electric cars are expensive, sales are increasing.

If, Unless (condition)

Two sentences: Governments invest in infrastructure. Economic growth will improve.

Combined: If governments invest in infrastructure, economic growth will improve.

When, After, Before (time)

Two sentences: Children start school. They develop social skills.

Combined: When children start school, they develop social skills.

Method 3: Participle Clauses

Start with an -ing or -ed verb to show cause or simultaneous action.

Two sentences: The government increased taxes. It raised $2 billion.

Combined: The government, increasing taxes, raised $2 billion.

Better: By increasing taxes, the government raised $2 billion.

Two sentences: Urban areas are overcrowded. They face housing shortages.

Combined: Overcrowded urban areas face housing shortages.

Common Mistakes

Mistake 1: Too Many Ideas in One Sentence

Bad: Children who spend too much time on devices, which are increasingly popular, suffer from health problems including obesity and poor eyesight, which are serious concerns.

This sentence tries to do too much. Split it:

Better: Children who spend too much time on devices suffer from health problems, including obesity and poor eyesight. These are serious concerns as device usage increases.

Mistake 2: Incomplete Clauses

Bad: Because technology advancing rapidly.

This isn't a complete sentence. You need an independent clause:

Correct: Because technology is advancing rapidly, workers must update their skills.

Mistake 3: Wrong Connector

Bad: Although fuel prices increased, therefore people bought smaller cars.

"Although" and "therefore" show opposite relationships. Pick one:

Correct: Because fuel prices increased, people bought smaller cars.

Correct: Fuel prices increased. Therefore, people bought smaller cars.

How Many Complex Sentences Do You Need?

Mix complex and simple sentences. If every sentence is complex, your writing becomes hard to read. Aim for 50-60% complex sentences in Task 2.

Simple sentences aren't bad. They provide clarity and rhythm. Use them to state your main points clearly. Use complex sentences to show relationships and add supporting details.

Practice Exercise

Take two simple sentences from your last practice essay. Combine them using one of the three methods above. Read both versions aloud. The combined version should sound smoother and more professional.