4 Types of Sentences by Structure and Function
One of the most important aspects of effective writing is using different types of sentences. Sentence variety keeps readers engaged and helps you communicate your ideas precisely.
In English writing, eight types of sentences are possible. There are four types of sentences by structure (simple, compound, complex, and compound-complex) and four types of sentences by function (declarative, interrogative, imperative, and exclamatory).
Whether you’re working on essays, cover letters, or personal correspondence, the tips and examples below will help you use all eight of these sentence types effectively and correctly. No matter what types of sentences you’re using, QuillBot’s free Grammar Checker can help you avoid errors.
Types of sentences by structure
One of the main ways to classify sentences is by structure, which affects the amount of information in a sentence and how it’s put together. The four types of sentence structures are simple, compound, complex, and compound-complex.
Simple sentences
A simple sentence is one independent clause, which has one subject and one predicate.
The subject performs the action of the sentence. It can be one noun or one subject pronoun (“I,” “we,” “you,” “he,” “she,” “they,” “it,” “who”). A simple sentence can also have a compound subject (two nouns or pronouns that perform the action of the sentence together).
A predicate includes one or more verbs and other information related to the verb (e.g., a direct object or adverbs). A simple sentence (or independent clause) can have a compound predicate (two verbs that share the same subject).
Who wants ice cream?
Cyclists and runners should drink beverages with electrolytes. [Compound subject]
Leopards sleep during the day and hunt at night. [Compound predicate]
Compound sentences
A compound sentence has two independent clauses that are separated by a comma and a coordinating conjunction (“for,” “and,” “nor,” “but,” “or,” “yet,” “so”) or a semicolon (;). Either of the independent clauses could stand alone as complete, simple sentences.
Hot tubs are relaxing, but they’re expensive to maintain.
Composition classes are important; everyone should be required to take them.
Would you like to come over for dinner tonight, or should we meet for brunch on Sunday?
Complex sentences
A complex sentence has an independent clause and one or more dependent clauses. The independent clause (also known as the main clause) could stand alone as a complete, simple sentence.
A dependent clause has a subject and a predicate, but it cannot stand alone as a complete sentence because it begins with a subordinating conjunction (e.g., “if,” “when,” or “because”). It depends on the main clause in order to make complete sense.
The independent clause can go first, last, or in the middle of a complex sentence. If a dependent clause goes first, use a comma to show where it ends. (You don’t need a comma before a dependent clause that goes after the independent clause, though.)
Don’t complain when the teacher assigns another essay.
How did the actor celebrate after he won the award?
Because I’m not a morning person, I don’t talk to anyone until I’ve had my coffee.
Compound-complex sentences
A compound-complex sentence has two independent clauses and at least one dependent clause. There are several ways to arrange the clauses depending on the relationship between the different ideas. Just remember:
- If a dependent clause begins a compound-complex sentence, use a comma to show where it ends.
- If you have two independent clauses next to each other, place a comma before the coordinating conjunction.
- You don’t need a comma before a dependent clause that follows an independent clause.
Lupita and Zoe both wore elegant suits to the Met Gala, but Lupita’s suit was more interesting because it included a cape.
The race will start at 7:00 if the weather is nice, but it will be delayed if it’s raining.
4 types of sentences by function
You can also classify sentences by four different functions (aka purposes):
- Declarative (statements)
- Interrogative (questions)
- Imperative (commands)
- Exclamatory (emotional statements)
Any of these types of sentences can also be simple, compound, complex, or compound-complex depending on how many independent and dependent clauses the sentence has.
A good piece of writing doesn’t necessarily need all four types of sentences by function, but when you do use any of these, follow the tips and examples below.
Declarative sentences
Declarative sentences are statements (as opposed to questions or commands). They’re the most common in formal writing. You can use declarative sentences for facts, opinions, explanations, or observations. The only end punctuation that you can use with a declarative sentence is a period.
Guinea pigs prefer lettuce, but hamsters like broccoli. [Compound declarative sentence]
The city needs to add more bike lanes because the roads are too crowded. [Complex declarative sentence]
If the team wins the Super Bowl, the city will have a parade, and school will be cancelled. [Compound-complex declarative sentence]
Interrogative sentences
An interrogative sentence is a question that ends with a question mark (?). The word “interrogative” is similar to the word “interrogate,” which means “to question aggressively.” Many interrogative sentences (aka questions) begin with one of these types of interrogative words:
- Interrogative determiners (“what,” “which,” and “whose”)
- Interrogative pronouns (“what,” “which,” “who,” “whom,” and “whose”)
- Interrogative adverbs (“when,” “where,” “why,” and “how”)
You can also make a tag question by adding a contraction (e.g., “isn’t” or “doesn’t”) with a pronoun (e.g., “he” or “it”) and a question mark (e.g., “It’s freezing outside, isn’t it?”).
Who played the main character in The Wild Robot, and what other movies has she made? [Compound interrogative sentence]
What will become the main source of energy when all of the fossil fuels are gone? [Complex interrogative sentence]
If the concert is cancelled, where should we go instead, and what time should we be there? [Compound-complex interrogative sentence]
Imperative sentences
You can use imperative sentences when you need to make demands or suggestions. In an imperative sentence, at least one independent clause uses the imperative mood, which means it has the following characteristics:
- The first word is the infinitive form of a verb (e.g., “watch” in “Watch out for flying monkeys”).
- The subject is the second-person pronoun “you,” but it’s implied rather than directly stated. The subject is the person (or people) you’re talking directly to.
Imperative sentences are useful when you’re writing instructions (e.g., instruction manuals, driving directions, recipes, or how-to essays).
Take a left on 34th Street, and look for the house with the golden door. [Compound imperative sentence]
If no one answers the door, leave the package on the white chair. [Complex imperative sentence]
When the butter begins to sizzle, add the onions, and sauté them for five minutes. [Compound-complex imperative sentence]
Exclamatory sentences
Exclamatory sentences are grammatically similar to declarative sentences except that they end in exclamation marks to show urgency or extra emotion. For example, you might use an exclamation mark to show excitement in a happy birthday message or frustration if you’re venting about a difficult situation to a friend.
Exclamatory sentences usually have a simple sentence structure for emphasis. The other sentence structures are technically possible but not very common in exclamations. A sentence can also be both exclamatory and imperative (e.g, “Keep this window closed at all times!”).
Your photograph looks amazing!
I can’t believe it’s snowing again!
Frequently asked questions about types of sentences
- What is the difference between a complex sentence and a compound sentence?
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Complex sentences are made up of one independent clause and at least one dependent clause.
Compound sentences are made up of two or more independent clauses connected with a comma and a coordinating conjunction or a semicolon (or, less commonly, with a colon or an em dash).
Complex vs compound sentence examples Complex sentence Compound sentence If it stops raining, I will go to the park. It stopped raining, so I went to the park. Kya was sleeping while the teacher was talking. The teacher was talking, and Kya was sleeping. QuillBot’s Paraphraser can help you use different types of sentences to add variety to your writing.
- What is the difference between a simple and compound sentence?
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Simple and compound sentences differ in their number of independent clauses (i.e., a group of words with a subject and verb that can stand on its own as a sentence).
- Simple sentences have one independent clause. For example: “Jack went shopping.”
- Compound sentences have at least two independent clauses joined by a comma and coordinating conjunction or a semicolon (or, less commonly, by a colon or em dash). For example: “Jack went shopping, and Lucy cooked dinner.”
Note that simple sentences can have compound subjects (e.g., “Jack and Lucy went shopping”) or compound predicates (e.g., “Jack went shopping and cooked dinner”) or both (e.g., “‘Jack and Lucy went shopping and cooked dinner”).
A compound sentence, in contrast, is formed when two full simple sentences are connected.
Use QuillBot’s Grammar Checker to make sure the types of sentences you’re using are structured correctly.
- Can a compound subject be used in a simple sentence?
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Yes, a compound subject can be used in a simple sentence—a sentence that has only one subject-verb pair (e.g., “Terrence and I like to hike).
Compound subjects can be used in all sentence types (i.e., simple, compound, complex, and compound-complex).
When you’re writing with different types of sentences and sentence subjects, the QuillBot Grammar Checker is a quick and easy way to proofread.
