Combining Sentences: Coordination and Subordination Explained

When you learn how to use coordination and subordination, you can turn short, choppy ideas into smooth, well-connected sentences. This makes your writing more mature, more logical, and more likely to earn top marks in exams like WAEC, NECO, IELTS, and TOEFL.

This guide will help you understand the difference between coordination and subordination, and show you how to use both correctly with examples and simple explanations.

Why Combine Sentences at All?

Imagine writing an essay filled with short, disconnected statements. It may be grammatically correct, but it will feel clumsy and hard to follow.

When you combine related sentences, you improve the flow and clarity of your writing. You also show the reader how your ideas are connected; whether they agree, contrast, or explain one another. Sentence combination is one of the easiest ways to make your writing sound polished and professional.

Coordination vs. Subordination: What’s the Difference?

There are two main ways to join sentences in English:

1. Coordination connects ideas that are of equal importance.
2. Subordination connects one idea that is more important with another that supports or explains it.

Both are useful, but they serve different purposes depending on what you want to say.

Coordination: Joining Equal Ideas

Coordination happens when you combine two independent sentences that are equally important. This is often done using coordinating conjunctions.

The most common coordinating conjunctions can be remembered using the word FANBOYS:
For, And, Nor, But, Or, Yet, So

Each of these words helps link ideas that stand alone but belong together in the same sentence.

For example:

• “She likes apples, and she likes oranges.”
  This tells us that both preferences are equally important.
• “He was late, so he missed the bus.”
  This shows that one event logically follows the other.

You can also use semicolons to coordinate ideas:

• “I was tired; I went to bed early.”

If you want to show contrast or cause using more formal connectors, you can use conjunctive adverbs with semicolons:

• “I studied hard; however, I didn’t pass the test.”

When using coordination, both clauses must be complete sentences that can stand on their own. You also need to use punctuation correctly, especially commas before conjunctions in longer sentences.

Subordination: Joining Unequal Ideas

Subordination is used when one idea is more important than the other. In this case, you make one clause dependent on the other. You do this by using subordinating conjunctions like:
because, although, since, if, when, unless, while, after, before, even though.

With subordination, you show that one clause explains or adds detail to the main idea.

For example:

• “He missed the bus because he was late.”
  The main point is that he missed the bus. The reason (he was late) is less important.
• “Although I wanted to go, I stayed at home.”
  The main focus is that you stayed at home. The first part simply explains the background.
• “If you work hard, you will succeed.”
  This sentence gives a condition that must be met before the result can happen.

You can place the subordinate clause before or after the main clause. If the subordinate clause comes first, always use a comma to separate it.

Coordination vs. Subordination: A Quick Comparison

Coordination is best when you want to show that both ideas are equally important. Subordination is better when you want to show that one idea depends on or explains the other.

Compare:

• Coordination: “I was tired, but I kept working.”
  This suggests both ideas are equally important.
• Subordination: “Although I was tired, I kept working.”
  This gives more importance to the fact that you kept working.

Understanding when to use each structure helps you write with purpose and clarity.

Mistakes to Avoid When Combining Sentences

Many students make common errors when trying to combine sentences. Let’s look at a few and how to avoid them.

Overusing Coordination

Too many connected clauses can make your writing sound flat or repetitive.

Wrong: “I woke up, and I brushed my teeth, and I ate breakfast, and I went out.”
Better: “I woke up, brushed my teeth, ate breakfast, and went out.”

In the second version, coordination is used more efficiently.

Misusing Subordination

Don’t force a subordinating conjunction into a sentence where it doesn’t fit.

Wrong: “Because I was tired, but I went to bed.”
Correct: “Because I was tired, I went to bed.”
Or: “I was tired, but I went to bed anyway.”

Each sentence must follow proper structure and meaning.

Using Comma Splices

A comma is not strong enough to join two complete sentences.

Wrong: “I was tired, I went to bed.”
Correct: “I was tired, so I went to bed.”
Or: “I was tired; I went to bed.”

Always use a conjunction or semicolon to avoid this error.

Practice Questions

Try combining the following sentence pairs using either coordination or subordination:

1. She was tired. She kept studying.
2. He missed the train. He arrived late at the station.
3. I studied hard. I passed the exam.
4. It rained. We went out to play.
5. You call me. I will come immediately.

Share your answers in the comments section.

Related Lessons

To build your skills further, check out:

• Common Sentence Patterns in English and How to Identify Them
• How to Build Clear and Effective Sentences in English Writing

These lessons complement what you’ve just learned and help you gain deeper control over English sentence construction.

Wrapping Up

Learning how to combine sentences properly helps you grow as a writer. When you use coordination and subordination with skill, your writing becomes smoother, smarter, and more engaging.

Practice combining sentences whenever you can, and in no time, your writing will become clearer, richer, and more effective.