Whereas sentence structure refers to the form of sentences in a language, sentence purpose refers to the function of sentences. Four types of sentence purposes exist in the English language: declarative sentences, interrogative sentences, imperative sentences, and exclamatory sentences.
The first type of sentence in the English language is the declarative sentence. Declarative sentences, or declarations, convey information or make statements. For example:
- My cat chases rabbits.
- Harry Potter is the boy who lived.
- Her brother has lived in Alabama for seven years.
- A tornado destroyed the grain bins.
- Duck and Goose were arguing over the ball.
- The trains leaves tomorrow promptly at noon.
Periods indicate declarative sentences in written English.
The second type of sentence in the English language is the interrogative sentence. Interrogative sentences, or questions, request information or ask questions. For example:
- When does the train leave?
- Do your dogs like peanut butter?
- How old is your daughter?
- Is your husband a firefighter?
- Have you brushed your teeth today?
- Would you like some more tea?
A tag question, or question tag or tail question, is a grammatical structure that converts a declarative or imperative sentence into a question through the addition of an interrogative fragment on the end of the sentence. For example:
- He didn’t take the train, did he?
- She has finished her degree, hasn’t she?
- You could wash the dishes, couldn’t you?
- I am going with you, aren’t I?
- Run to the store, will you?
- Let’s have some ice cream, shall we?
Question marks indicate declarative sentences in written English.
The third type of sentence in the English language is the imperative sentence. Imperative sentences, or imperatives, make commands or requests. For example:
- Bring me some sugar.
- Buy some bread and milk on your way home.
- Shut the door please.
- Turn right at the park.
- Stop talking so loudly!
- Open the windows to let the smoke out!
Periods indicate imperative sentences in written English.
The fourth type of sentence in the English language is the exclamatory sentence. Exclamatory sentences, or exclamations, show emphasis. Unlike the other three sentences purposes, exclamatory sentences are not a distinct sentence type. Instead, declarative, interrogative, and imperative sentences become exclamatory through added emphasis. For example:
- You broke the lamp! (declarative)
- The train left an hour ago! (declarative)
- How did you break your leg?! (interrogative)
- What the heck was that?! (interrogative)
- Stop chewing with your mouth open! (imperative)
- Do not open the presents until the morning! (imperative)
Exclamation marks and interrobangs indicate exclamatory forms of sentences in written English.
The four types of sentence purposes in the English language are declarative sentences, interrogative sentences, imperative sentences, and exclamatory sentences.
Brinton, Laurel J. & Donna M. Brinton. 2010. The linguistic structure of Modern English, 2nd edn. Amsterdam: John Benjamins Publishing Company.
Hopper, Paul J. 1999. A short course in grammar. New York: W. W. Norton & Company.
Huddleston, Rodney. 1984. Introduction to the grammar of English. Cambridge: Cambridge University Press.