What Are Compound Sentences?
Compound sentences are sentences that have at least two independent clauses. These independent clauses are combined by a comma, semicolon, or conjunction.
What Is an Independent Clause?
This dress is too expensive, and that hat is too small.
This sentence is a compound sentence, because it has two independent clauses, 'This dress is too expensive' and 'that hat is too small' separated by a comma and the conjunction 'and.'
Coordinating conjunctions (also called coordinators) are used with commas and semicolons to join independent clauses together. Here are the coordinators you can use to join independent clauses:
Note that they form the handy mnemonic FANBOYS.
The most common coordinators are 'and,' 'but' and 'or.'
However, as mentioned earlier, compound sentences can also use a semicolon to connect two clauses, in which case no conjunction is necessary.
What Are Compound Sentences Used for?
For writing a fluent and fast-paced text, we can use compound sentences. They are best for combining two or more complete and related sentences into a single one. A compound sentence brings together individual, related sentences as one.
Simple sentence #1: I have a pet hamster.
Simple sentence #2: Its name is Frodo.
Compound Sentence: I have a pet hamster, and its name is Frodo.
To combine them into a compound sentence, we simply add a comma plus the coordinator 'and'.
I have a pet hamster; its name is Frodo.
Alternatively, we can make a compound sentence by adding only a semicolon and the sentence is still correct.
Even though these two simple sentences talk about the same thing, the subjects of each sentence are different: the subject of the first sentence is I and the subject of the second one is name. That's why they are considered independent clauses and compound sentences only work with independent clauses. Now, look at the example below which is not a compound sentence:
I have a pet hamster whose name is Frodo.
This sentence needs at least two subjects and two verbs to be a compound sentence. If both sentences use the same subject, it must be stated twice. Otherwise, it’s not a compound sentence.
Be careful with the sentences that have two subjects or two verbs. They are not necessarily the same as compound sentences. The following sentence is not a compound sentence, because:
- There is only one subject
- What comes after the conjunction 'and' is not an independent clause
He went to a restaurant to eat lunch and meet his friends.
However, this sentence can be turned into a compound sentence by adding another independent clause with a second subject:
He went to a restaurant to eat lunch and meet his friends, but he forgot to bring his wallet.
Beware that imperatives normally do not show their subjects, because they are implied. So this imperative sentence is a compound sentence:
Come here at once, or I will come to you!
When you are writing a compound sentence, you can use two ways to combine independent clauses together:
- put a comma before the coordinating conjunction
- (in case of not using a coordinating conjunction), put a semicolon between each clause
Joining Compound Sentences with Conjunctive Adverbs
We can also join independent clauses with conjunctive adverbs like:
- at least
In this case, the conjunctive adverb must be preceded by a semicolon (;) and followed by a comma (,).
A compound sentence joins two or more related sentences of equal importance. Each sentence or independent clause must still have a subject and a verb.
She preferred garden salad; he wanted a burger.
She went to the park, but he stayed at home.