What are Compound Sentences? - Meaning, Types, Rules, Examples and Exercises with Answers

A compound sentence is a type of sentence that combines two or more independent clauses, each capable of standing alone as a complete sentence, into one sentence. These clauses are usually joined by coordinating conjunctions such as for, and, nor, but, or, yet, and so (FANBOYS). Sometimes, a semicolon or a conjunctive adverb like however, therefore, or moreover can also be used to link the clauses. The purpose of a compound sentence is to show that the ideas in the clauses are closely related and are equally important.

For example:

• I wanted to go to the gym, but it started to rain.
• She is very tired, yet she continues to work hard.
• He can come with us, or he can stay home.

In the examples above, both parts could stand alone, but they are combined to express a contrast.

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According to Oxford dictionary, “A compound sentence is a sentence that is composed of two or more main clauses, or independent clauses, that are joined together.”

As mentioned in the Cambridge Dictionary, “A sentence made from two independent sentences joined by ‘and’, ‘or’ or ‘but’, as in Mary read and Tom slept.”

Examples include:

• I don’t like coffee, nor do I enjoy tea.
• It was raining, so we stayed indoors.
• I finished my work; I went out to play.
• He didn’t study; therefore, he didn’t do well on the test.
• The sun is setting; the sky looks beautiful.

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In English Grammar, compound sentences are categorized based on how the independent clauses are connected. While the basic structure remains the same, i.e. two or more independent clauses, the type of connector used determines the type of compound sentence.

There are three types of compound sentences. Let us know them below:

1. Using Coordinating Conjunctions (FANBOYS)

A compound sentence using coordinating conjunctions connects two or more independent clauses with the word from FANBOYS group: For, And, Nor, But, Or, Yet, So. The coordinating conjunction links the equal yet stand-alone ideas showing relationships like addition (and), contrast (but, yet), choice 9or0, cause (for, so) or negation (nor). A comma is placed before the coordinating conjunction when joining the clauses.

Examples:

F: She was tired, for she had worked all day.

A: I went to the market, and I bought some vegetables.

N: He doesn’t like tea, nor does he enjoy coffee.

B: She wanted to go out, but it started raining.

O: You can have coffee, or you can have juice.

Y: She is very young, yet she is very wise.

S: It was raining, so we stayed indoors.

2. Using a semicolon

A semicolon-type of compound sentence is formed by joining two independent clauses using a semicolon (;) instead of a coordinating conjunction. A semicolon is used to show a close relationship between two ideas without using words like but, and, or so. It links two related thoughts in a single sentence without repeating a subject or using a conjunction. This type of compound sentence is useful when you want to connect ideas clearly and directly, especially when the relationship between them is obvious.

For example:

• The movie was long; the audience didn’t seem to mind.
• She loves to paint; her brother prefers photography.
• He didn’t call me; I called him instead.
• They arrived late; the meeting had already started.
• Meena studies hard for the test; she stull didn’t pass.

Also Read: Punctuation Marks in English- Types, Uses, How to Master Punctuation

3. Using a semicolon and a conjunctive adverb

A compound sentence using a semicolon and a conjunctive adverb joins two independent clauses with a semicolon followed by a conjunctive adverb (such as however, therefore, moreover, consequently, nevertheless, etc.) and then a comma before the second clause. This type of sentence structure shows a more specific relationship between two ideas such as contrast, cause and effect, or addition. This form is often used in formal or academic writing to clearly express logical connections between related ideas and to maintain smooth, professional sentence flow.

For example:

• The hotel was expensive; still, we decided to stay there.
• They arrived on time; in fact, they were the first ones there.
• The road was blocked; nevertheless, we found another way.
• She studied all night; therefore, she performed well on the exam.
• I love classical music; moreover, I play the piano.

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To correctly form a compound sentence, certain rules must be followed. One common method is using a coordinating conjunction; another method is by using a semicolon to join related independent clauses without a conjunction. A third method is combining the two methods, using a semicolon followed by a conjunctive adverb. Proper punctuation and clear connection of ideas are key to constructing grammatically correct and meaningful compound sentences. Let us list down the rules of compound sentences below:

1. Compound sentences must contain at least two independent clauses

An independent clause is a group of words that forms a complete thought and has both a subject and a verb and these clauses are usually joined by a coordinating conjunction like and, but, or, so, yet, not or for.

For example:

• She is reading, and he is writing
• She likes coffee, and he prefers tea.
• He didn’t study for the exam, but he still passed with flying colours.

2. Use commas with coordinating conjunctions (FANBOYS)

In a compound sentence, when you join two independent clauses using a coordinating conjunction (FANBOYS), you must place a comma before the conjunction.

This rule helps separate the two complete thoughts and makes the sentence easier to read and understand.

For example:

• I was tired, but I kept working.
• You can call me, or you can send a message.
• It was late, so we decided to go home.

3. Semicolons are used in compound sentences

Compound sentences use a semicolon to join closely related clauses. A semicolon is used when you don’t use a conjunction but still want to show a relationship.

For example:

• I have a big test tomorrow; I can’t go out tonight.
• The sky darkened quickly; a storm was approaching.
• You must wear a seatbelt; it’s the law.

4. Compound sentences use semicolon and conjunctive adverb, and comma

Compound sentences use semicolon and conjunctive adverb and comma for clearer relationship. First a semicolon is used, then a conjunctive adverb (moreover, however, therefore, etc.) followed by a comma.

This structure helps show the precise relationship between the two ideas – such as contrast, result, addition or sequence.

For example:

• She didn’t study; therefore, she didn’t pass.
• He didn’t see the stop sign; therefore, he got a challan.
• I wanted to go hiking; however, it started to rain.

5. Avoid comma splices

A comma splice is a common grammar mistake that happens when two independent clauses are joined with only a comma – without a coordinating conjunction or proper punctuation like a semicolon.

This is incorrect because a comma alone is not strong enough to connect two complete thoughts.

For example:

Incorrect: I was tired, I went to bed.

Correct: I was tired, so I went to bed.

Correct: I was tired; I went to bed.

Also Read: Know how you can improve your English vocabulary

While compound sentences in English follow standard rules, there are some special cases and exceptions to be aware of. Sometimes a coordinating conjunction is used without a comma when the clauses are very short and closely related. In informal speech or writing, people may also use comma splices. Let’s read about such special cases and exceptions here.

1. Omission of second subject (Ellipses)

Sometimes a subject in the second clause is omitted when it is the same as in the first. This is done to make the sentence more concise and natural sounding, especially in informal speech or writing.

However, the second clause must be clearly understood and closely related to the first.

Examples:

• She cooked dinner and (she) cleaned the kitchen.
• He grabbed his bag and (he) ran out the door.
• I wanted to stay but (I) had to leave.

2. No comma before short clauses

Writers often omit the comma before the coordinating conjunction if the second independent clause is very short.This is done to keep the sentence smooth and avoid unnecessary punctuations that might interrupt the flow.

Examples:

• He ran and he won.
• She came and I left.
• Stay here or go home.

3. Repeated coordinating conjunctions

Some compound sentences use multiple conjunctions to link three or more clauses. This allows a writer to express several related ideas in one smooth sentence, making the writing more fluid and connected.

Examples:

• I woke up, and I got dressed, and I left for school.
• He laughed and laughed and laughed until his stomach hurt.
• You can eat pizza or pasta or salad or soup – whatever you like.

4. Coordinating conjunctions starting a sentence

You can begin a sentence with and, but or so for effect, but only when the sentence is not a fragment. This is acceptable in modern writing for emphasis.

These words are coordinating conjunctions (part of FANBOYS group) and when used at the beginning of a sentence, they can add emphasis, improve floe, or create a natural, conversational tone.

Examples:

• But he didn’t agree.
• And then he disappeared into the crowd.
• So I decided to take the risk.

Also Read: Punctuation in English Grammar; Usage, Type, Definition

Compound sentences are most effective when you want to:
• Show a clear relationship between ideas.
• Avoid short, choppy sentences.
• Show contrast or choice
• Make writing more persuasive or emphatic
• Add variety to sentence structure

Compound sentences and complex sentences are both used to combine ideas, but they do so in different ways. Let’s read their differences below: