In linguistics, the sentence is a unit of language, characterised in most languages by the presence of a finite verb. For example, "The quick brown fox jumped over the lazy dog." The shortest legal sentences in the English language are "I am" and "I do" - although with some bending of the rules, the imperative "Go!" can be considered a sentence, as could the word "I", carrying an unspoken verb "am" in response to a question such as "Who's in charge here?"

Traditionally, each sentence is regarded as having a subject, an object and a verb, even if one of these is implied. See grammar for more details. The objects that modify the noun phrase collectively form the predicate of a sentence.

In the English language, linguists classify sentences into one of four types based on their structure:

1. Simple sentence
2. Compound sentence
3. Complex sentence
4. Compound-complex sentence

Sentences can also be classified based on their purpose:

Declarative sentences (Declarations)

Used to state a fact or argument that does not require a response from the listener. For example:

I am going home.

Interrogative sentences

Used to ask a question that expects an answer from the listener. For example:

When are you going to work?

Rhetorical questions

Appears in the form of a question that is not expected to be answered by the listener and generally used emphasize a statement or argument. For example:

Who am I to question his authority?

Exclamatory sentences (Exclamations)

Used to make a forceful or emphatic statement or argument. Can also be an interjection. For example:

This is such a wonderful day!

Wow!

Imperative sentences (Imperatives)

Used to give a direct command or request to the listener. Can also appear in the form of a question. For example:

Go do your homework.

Would you please pass the bread?

An incomplete sentence is called a sentence fragment.