There are four types of sentence in English and one of them is called the compound-complex sentence. In this article, I will tell you everything you need to know about them.

Clauses and Sentence Types

Before we look at compound-complex sentences, let’s review clauses and sentence types just briefly. (If you already know this, you can skip ahead to the next section.)

We have two types of clause:

  • Independent
  • Dependent

An independent clause is one that could function by itself as a sentence because it possesses the following three things:

  1. Subject
  2. Verb
  3. Complete thought

A dependent clause, however, lacks at least one of these things and cannot function as a complete sentence. It merely expands upon an independent clause.

Keeping that in mind, we have four types of sentence in English:

Sentence TypeMeaningExample
Simple1 independent clauseIt is raining.
Compound2 independent clausesI want to play football, but it is raining
Complex1 independent + 1 dependent clauseI want to play football even though it is raining.
Compound-complex2 independent + 1 dependent clauseI want to play football even though it is raining; however, my parents won’t let me.

You can learn more about sentence types here. You might also appreciate my free grammar course.

What is a Compound-Complex Sentence?

As we have seen, there are compound sentences and complex sentences. A compound-complex sentence is a mix of the two forms. It contains at least two independent clauses and one dependent clause. For example:

  • I woke up at six o’clock because I had to hit the gym, but I was too tired to get out of bed.

This sentence is made up of three clauses:

  1. I woke up at six o’clock (independent)
  2. Because I had to hit the gym (dependent)
  3. But I was too tired to get out of bed (independent)
compound-complex sentence formula

Clause Order in Compound-Complex Sentences

In a compound-complex sentence, the clauses can come in any order. For example:

Clause orderExample
Independent + independent + dependentI am hungry, but my fridge is empty because I forgot to go shopping.
Independent + dependent + independentMy fridge is empty because I forgot to go shopping, but I am hungry.
Dependent + independent + independentBecause I forgot to go shopping, my fridge is empty, but I am hungry.

You can see that we can play around with the order of clauses. However, keep in mind that you need to convey your ideas effectively. In the above examples, all three are correct but the first one is by far the clearest. Note the sequencing of ideas:

  1. I am hungry (this is the main point of the sentence)
  2. But my fridge is empty (this is why we are being told about the hunger)
  3. Because I forgot to go shopping (this is an explanation of the previous clause)

Always arrange your sentences according to the importance of the ideas expressed and try to convey your ideas logically and simply.

How Many Clauses are in a Compound-Complex Sentence?

We usually define a compound-complex sentence as having at least 2 independent clauses and 1 dependent clause. That means there should be at least three clauses in the sentence.

The examples we have seen above all contained three clauses, but here’s an example with four:

  • Even though she bought a new computer, she kept her old one, and she still uses it because it has some important programmes.

Here, we have four clauses:

  1. Even though she bought a new computer (dependent)
  2. she kept her old one (independent)
  3. and she still uses it (independent)
  4. because it has some important programmes (dependent)

We could expand this to five clauses:

  • Even though she bought a new computer, she kept her old one, and she still uses it because it has some important programmes that she couldn’t install on the new one.

The clauses are:

  1. Even though she bought a new computer (dependent)
  2. she kept her old one (independent)
  3. and she still uses it (independent)
  4. because it has some important programmes (dependent)
  5. that she couldn’t install on the new one (dependent)

This is a great way to incorporate lots of ideas into a sentence instead of using many short sentences. However, be aware that long sentences can present new problems. You should avoid overcomplication in your IELTS essays.

Generally, academic writing tends to include quite long sentences but you certainly want to avoid ridiculously complicated sentences. If you make one tiny mistake, it can cause the whole sentence to fall apart. Even if you get it right, it can be a strain for your reader. Thus, compound-complex sentences are usually around 3-5 clauses in length.

Punctuation in Compound-Complex Sentences

Compound-complex sentences are made up of compound and complex sentences and so you should try to follow the punctuation rules that apply to these. For example:

Punctuation RuleExample
Put a comma between two independent clauses if they are joined by a coordinating conjunction.The living room is big, but the kitchen is bigger.
Put a semi-colon between two independent clauses if they are joined by a conjunctive adverb. A comma should go after that adverb.The living room is big; however, the kitchen is bigger.
Put a comma between a dependent and independent clause when the dependent one comes first.Although the living room is big, the kitchen is bigger.

There are also rules regarding relative clauses. These are a little too complex to explain here, but you can read all about them in this article if you need.

Let’s expand the above examples into a compound-complex sentence:

  • The living room is big, but the kitchen is bigger because they really love cooking.

This sentence is structured: independent + independent + dependent. Because there is a coordinating conjunction between the two independent clauses, we use a comma. The dependent clause comes at the end, so there is no comma before it.

Here’s another example:

  • Although the living room is big, the kitchen is bigger, so everyone gathered in there during the party.

This sentence is structured: dependent + independent + independent + dependent. A dependent clause comes first, so it is followed by a comma. The two independent clauses are split by a comma. The final dependent clause follows an independent one, so there is no comma used.

Easy!

You can read more about commas here. There is a guide to semi-colons here. More general punctuation advice can be found here.

Conclusion

Compound-complex sentences often seem difficult but actually there aren’t many rules to consider and, with a little practice, they are quite easy to learn. Keep in mind the rules about clauses and punctuation and you should be able to start making your own compound-complex sentences. Just keep in mind two things: 1) Don’t make your sentences too long or they will likely fall apart; 2) Ensure that the order of ideas in your sentences is logical enough for any reader to follow it.