Compound-Complex Sentences 101: Explanation and Examples

Ready to master the most complicated standard English sentence structure? In this guide, you’ll find a definition, explanation and tons of examples of compound-complex sentences.

Compound-complex sentences are one of the four essential sentence types. These are

• Simple sentences

• Compound sentences

• Complex sentences

• Compound-complex sentences

Each sentence type uses a different combination of independent and dependent clauses. (If you’re unfamiliar with clauses, you may want to review this article on English sentence structure!) Compound-complex sentences have more clauses than other types of sentences, making them the most difficult to tackle.

That said, they’re also incredibly common and useful in spoken and written English. Compound-complex sentences help us communicate complicated relationships between things and ideas and add style and variety to writing.

In this guide, you’ll learn all about compound-complex sentences, with easy-to-understand explanations, rules for putting a compound-complex sentence together, and exercises and examples of compound-complex sentences. By the end of this article, you should be able to identify and build compound-complex sentences with confidence!

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Simple explanation (and examples!) of compound-complex sentences 

Ready to master compound-complex sentences?

Let’s start by reviewing the sentence types.

Simple sentences are made up of one independent clause – in other words, a single clause that forms a complete sentence. For example:

I write simple sentences.

Compound sentences are made up of two independent clauses, joined by a coordinating conjunction, dash or semicolon.

I can write simple sentences, but I like to write compound sentences.

Complex sentences are made of one independent and one dependent clause – one clause that can stand alone as a full sentence and one that can’t.

While compound sentences are nice, complex sentences are my favorite.

With these definitions in mind, compound-complex sentences are easier to understand. They combine compound and complex sentences.

What are compound-complex sentences?

Compound-complex sentence definition

A compound-complex sentence is a sentence formed from two independent clauses and one dependent clause. 

For example:

While simple sentences are good for beginners, compound and complex sentences are very useful, and compound-complex sentences will add style and nuance to your writing.

Or here’s a simpler example:

“I went to the store, but I didn’t buy anything because I forgot my wallet.”

We’ll show you how to identify the dependent and independent clauses in each sentence next.

Compound-complex sentence parts

In essence, a compound-complex sentence is the marriage of a compound sentence and a complex sentence. Because of this, a compound-complex sentence will typically require both a coordinating conjunction and a subordinating conjunction.

Let’s look at the different parts that make up a compound-complex sentence.

Independent clause

An independent clause is a complete sentence. It has a subject and a verb and can stand alone according to English sentence structure rules.

Dependent clause

A dependent clause is a group of words with a subject and verb that cannot stand alone in English grammar and does not form a complete sentence. You can frequently identify a dependent clause because it starts with a word like “while,” “because,” or “although,” also known as a subordinating conjunction. (We’ll cover subordinating conjunctions below.)

Coordinating conjunction

A coordinating conjunction is a conjunction used when connecting words, phrases and clauses of equal grammatical value. You can remember the seven coordinating conjunctions using the acrostic FANBOYS:

• For

• And

• Nor

• But

• Or

• Yet

• So

Subordinating conjunction

A subordinating conjunction is a word or phrase that creates a dependent clause. The addition of a subordinating conjunction makes the clause an incomplete thought, meaning it can’t stand alone. Unlike coordinating conjunctions, there are many, many subordinating conjunctions.

Here are a few of the most common:

• Since

• Before

• After

• Until

• When

• While

• As soon as

• As long as

• If

• Though

• Although

• Even though

• Because

• Unless

• In case

• Where

• Wherever

• Whereas

• Just as

• As if

Examples of compound-complex sentences

With those parts of speech in mind, let’s break down the examples of compound-complex sentences we’ve seen already.

I went to the store,

I didn’t buy anything

While simple sentences are good for beginners,

compound and complex sentences are very useful

compound-complex sentences will add style and nuance to your writing

Key:

• Underline = Independent clause

  – a complete sentence

• Italics = Dependent clause – an incomplete thought starting with a subordinating conjunction

• Bold = Coordinating conjunction – connects equal clauses

• Bold italics = Subordinating conjunction – creates a dependent clause

Essential grammar: Compound-complex sentences 

Now that you’ve learned about the parts that make up a compound sentence, let’s try putting some new compound sentences together.

How do you form a compound-complex sentence?

To put together a standard compound-complex sentence, let’s start with three statements.

I bought a house. 
I sold my car.
My new house is in the city.

Now, let’s think about ways to express the relationship between these sentences using conjunctions. We need one coordinating conjunction and one subordinating conjunction.

How about but (coordinating conjunction) and because (subordinating conjunction)?

Let’s use them to create one compound sentence and one complex sentence.

I bought a house, but I sold my car.
I sold my car because my new house is in the city.

And to turn these two pieces into one compound-complex sentence, we can simply combine them.

I bought a house, but I sold my car because my new house is in the city.

Let’s try that again.

Here are three complete sentences:

I love my cat.
She sheds a lot.
I would do anything for her.

And here they are with conjunctions added to form a compound-complex sentence:

Even though she sheds a lot, I love my cat, and I would do anything for her.

Why use compound-complex sentences?

As you can see from the above examples, coordinating and subordinating conjunctions can help create and express relationships between seemingly separate thoughts. Three simple sentences tell more of a story when combined into a compound-complex sentence. 

This makes it possible to express more complex thoughts and relationships. Plus, it’s a helpful tool for any writer’s toolbox, giving you the ability to vary sentence length and style to keep readers engaged. Ideally, you would use all four of the standard sentence structures at different points in your writing.

Choosing a conjunction

While coordinating conjunctions are pretty limited, there are tons of subordinating conjunctions in the English language!

In general, you can think of these conjunctions as falling into a few different categories based on how they’re used. There are subordinating conjunctions that

1. Explain cause and effect or purpose – like “as” and “because”

2. Add time, place or manner – like “before,” “after,” “as long as,” “since,” “wherever,” and “until”

3. Describe conditions – like “unless,” “in case,” and “if”

4. Make concessions or show contrast – like “although,” “while,” and “even if”

For a more complete list and explanations, take a look at this guide to subordinating conjunctions.

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Compound-complex sentence rules and style guidelines

Now for a few final guidelines to help you use compound-complex sentences correctly.

Punctuation

As you may recall if you’ve learned about compound sentences, if you want to get fancy, you can use a semicolon or dash. That applies to the compound aspect of compound-complex sentences too. Let’s take another look at our earlier example.

Even though she sheds a lot, I love my cat, and I would do anything for her.

Even though she sheds a lot, I love my cat; I would do anything for her.

Even though she sheds a lot, I love my cat – I would do anything for her.

All three of these options are grammatically correct.

Essentially, when it comes to punctuation, the rules that apply to complex sentences and compound sentences apply to compound-complex sentences.

• When a dependent clause comes first, it will be joined to the next clause with a comma.

• When a dependent clause comes in the middle of a sentence, it should be offset with commas on either side.

• When joining two independent clauses, a comma comes before the coordinating conjunction.

• If no coordinating conjunction is used, independent clauses may also be joined by a dash or semicolon, but this is less common.

• When a dependent clause comes at the end of the sentence, no comma is needed to join it to the preceding independent clause unless it is non-restrictive – meaning it’s not essential to the meaning of the sentence.

Punctuation is key to making your writing clear, so be sure to pay attention to it!

Three rules to remember

Besides punctuation rules, there are a few compound-complex sentence rules you might want to remember.

1. Don’t be afraid to use shorter sentences for clarity.

2. Watch out for run-on sentences or sentences that grow too long and unclear.

3. Consider meaning and choose your conjunctions and clause order wisely.

Examples and exercises for compound-complex sentences 

Now we’ve covered all the basics of compound-complex sentences. All that’s left to do is get a feel for reading them, writing them and using them in spoken English.

Examples

Below, you’ll find several examples of compound-complex sentences. Read them, think about what they might mean and try saying them out loud to get a feel for their rhythm.

As soon as I got to the office, I realized I’d forgotten my lunch, and that was the start of a very bad day.

You went to the cafeteria, wherever that is, so I ate at my desk.

She loves music, and she loves dogs, provided that they aren’t too loud.

In case a fire starts, there’s an extinguisher in the kitchen – we’ll show you where.

They aren’t party animals, but they can be fun once bingo gets going.

I told him I could meet him at the dock, but he said he’d call me when he got in unless his phone died.

We left you money so that you could buy a pizza; we put it on the hallway table.

Exercises

Now that you’ve seen quite a few different ways to put a compound-complex sentence together, try it for yourself!

Here are a few exercises you can try:

• Break down the examples above into their clauses and conjunctions.

• Make a list of simple sentences and practice finding new ways to combine them.

• Put together a list of subordinating conjunctions and try to use each one in a compound-complex sentence.

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