We all know what sentences are, but do you know the different types of sentence structures and how to form them?
There are four different types of sentences in English; simple sentences, compound sentences, complex sentences, and compound-complex sentences. This explanation is all about compound sentences.
Keep reading to find out more, and see some examples of compound sentences. (p.s that's a compound sentence!)
Compound sentence meaning
A compound sentence is a sentence that consists of two or more independent clauses. This is easy to remember, as the word 'compound' means something composed of two or more elements!
We categorise sentence types based on the number and type of clauses they contain. In the case of compound sentences, they:
Are made up of two or more independent clauses
Do not contain any dependent clauses
Join together independent clauses with a comma and a coordinating conjunction or with a semicolon (;).
Clauses are the building blocks of sentences. There are two types of clauses: independent and dependent clauses.
Independent clauses work on their own, and dependent clauses rely on other parts of the sentence. Every clause, independent or dependent, must contain a subject and a verb.
First, we're going to look at how compound sentences are formed and provide some examples. Then, we will use this information to identify compound sentences and distinguish them from other kinds of sentences.
Compound sentence structure
A compound sentence is made up of two or more independent clauses joined together by a comma and a coordinating conjunction or with a semicolon (;). Compound sentences do not contain any dependent clauses. Below, we can see the structure of a compound sentence:
Independent clause + connective (comma and a coordinating conjunction or a semicolon) + independent clause
I like Italian food, but my partner likes Chinese food.
In the above example, the two independent clauses are 'I like Italian food' and 'My partner likes Chinese food.' Both clauses make sense as standalone sentences.
Fig 1. I love Chinese food, and I'm not afraid to show it!
Joining independent clauses in compound sentences
As previously mentioned, compound sentences are formed by joining two independent clauses together. It's very easy to make a mistake here, so let's try and clear up any confusion and address the common mistakes that are made when creating compound sentences.
First, make sure you are joining two independent clauses. Independent clauses can be easily confused with dependent clauses or with phrases.
An independent clause must:
Include a subject and a verb. They can also include an object and/or a modifier.
Work on their own. Unlike dependent clauses, they don't rely on another clause to make sense.
Ask yourself, 'can these clauses work as sentences on their own?' Compound sentences are generally made by joining two or more simple sentences together.
I was walking the dog. I was restless.
If we replace the full stop that separates the sentences with a comma and a coordinating conjunction, these two sentences become one compound sentence:
I was walking the dog, for I was restless.
Each clause must have a subject and a verb; otherwise, it is not a compound sentence. In the above compound sentence, you can see two subjects (I and I ) and two verbs (walking and was).
The following example is not a compound sentence as it only contains one subject.
I am tired and need to sleep. (not a compound sentence)
However, if we add a subject and use the appropriate connectives, we can form a compound sentence like so;
I am tired, and I need to sleep. (compound sentence)
Imperative sentences and subjects
In imperative sentences (sentences which give a demand, e.g. sit down) the subject is often assumed rather than physically spoken or written. Although we cannot see the subject, it is still there, and imperatives can still be considered independent clauses. For example, 'Sit down, or else you'll be in trouble.' In the first clause, the subject is you, i.e (you) sit down.
Coordinating conjunctions in compound sentences
You'd heard us say a few times now that compound sentences are formed by joining two independent clauses together with coordinating conjunctions but what exactly are they?
Coordinating conjunctions are joining words that join clauses together that have equal weight, i.e. two independent clauses rather than an independent and a dependent clause. An easy way to remember coordinating conjunctions is with the mnemonic FANBOYS.
Compound sentences and punctuation
Using the correct punctuation is an important part of forming compound sentences. There are two correct ways to use punctuation;
- A comma followed by a coordinating conjunction (e.g. Peter has a bike, and Ana has a scooter.)
- A semicolon without a coordinating conjunction (e.g. Peter has a bike; Ana has a scooter.)
Comma splices
A common grammar mistake many people make when forming compound sentences is the comma splice. A comma splice is when two independent clauses are joined together with only a comma - this is incorrect and should be avoided! For example, 'Spiders have eight legs, they are arachnids.' is a grammatically incorrect sentence. When joining two independent clauses, we must use a comma alongside a coordinating conjunction or a semicolon. E.g. 'Spiders have eight legs; they are arachnids.'
Fig 2. Be careful with punctuation when forming compounding sentences
Examples of Compound Sentences
Here are some examples of compound sentences. Try to spot the subjects, verbs, and links between each one.
I like drinking tea, and Mandy likes drinking coffee.
Our car broke down, so we arrived last.
John went to the party; I went home.
They spoke with him in French, but I spoke with her in German.
Below, we have broken each sentence down. The subjects are in bold, the verbs are in blue, and the links are in red.
I like drinking tea, and Mandy likes drinking coffee.
Our car broke down, so we arrived last.
John went to the party; I went home.
They spoke to him in French, but I spoke to her in German.
Why are compound sentences used?
We use compound sentences in both spoken and written English. They are used to link independent ideas together. By having multiple independent clauses in the same sentence, we can link ideas that would have otherwise been separated.
Furthermore, by combining what would otherwise be lots of simple sentences in one text, compound sentences can make writing more interesting.
Here is an example passage that only uses simple sentences:
I went for a walk. I was tired. I came home. I decided to have dinner. I cooked pasta.
Notice how, with all the sentences being simple, the passage begins to feel boring and repetitive. Now, here's the same passage again but with compound sentences:
I went for a walk, but I was tired, so I came home. I decided to have dinner, so I cooked pasta.
By linking the simple sentences together and making them into compound ones, the short passage has become much easier to read and doesn't seem as dull!
How to identify a compound sentence
We can identify compound sentences by considering the type and amount of clauses in that sentence.
Simple sentences only contain one independent clause.
Compound sentences contain two (or more) independent clauses joined by a coordinating conjunction.
Complex sentences contain one independent clause and one (or more) dependent clause joined by a subordinating conjunction.
Compound-complex sentences contain at least two independent clauses and at least one dependent clause.
There are always multiple clauses in compound sentences, and these clauses are always independent. So, if you are trying to identify whether a sentence is a compound sentence - check for multiple independent clauses!
Compound Sentence - Key takeaways
A compound sentence is one of four types of sentences. The others are simple sentences, complex sentences, and compound-complex sentences.
A compound sentence comprises two or more independent clauses. Each independent clause contains a subject and a verb and can work on its own.
Compound sentences are useful when trying to link together multiple ideas.
You can identify compound sentences by looking at the number and type of clauses. If they are all independent clauses and there is more than one clause, you know it's a compound sentence.
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