A simple sentence expresses one complete idea with one main clause. It always has a subject and a verb, and it can stand alone as a complete thought. It can be short or long, but it does not contain another sentence inside it.

The subject is who or what the sentence is about. It is usually a noun or pronoun, and it often comes before the main verb in English. A subject can be one word or a full noun phrase with determiners and adjectives.

The main verb shows an action, event, or state, and it is the core of the sentence. Every simple sentence has exactly one main clause, so it has one main verb phrase. The verb may be a single word or include helping verbs.

The most common simple-sentence order in English is Subject–Verb–Object or Subject–Verb–Complement. English relies heavily on word order to show roles, so changing the order can change the meaning. Questions and some emphasis patterns can change the order, but the idea is still one main clause.

Rule	Example
Use Subject–Verb as the core	She smiles.
Add an object after the verb for transitive verbs	He reads a book.
Put time and place phrases after the core clause	They met yesterday at the station.

An object receives the action of the verb. Direct objects answer what or whom after the verb, and they usually come right after the verb. Some verbs can also take an indirect object, which often refers to the receiver.

A complement completes the meaning of certain verbs, especially be, become, seem, and feel. Subject complements describe or identify the subject, often as a noun phrase or adjective. Complements are not objects because they do not receive an action.

Modifiers add extra information but are not required for the sentence to be complete. Adjectives modify nouns, and adverbs modify verbs, adjectives, or other adverbs. Prepositional phrases and other phrase types can also act as modifiers in a simple sentence.

Helping verbs combine with a main verb to express tense, aspect, voice, or mood. Even when there is a helping verb, the sentence can still be simple because it is still one main clause. Common helping verbs include be, have, and do, as well as modal verbs like can and should.

Rule	Example
Use be + -ing for actions in progress	She is studying.
Use have + past participle for completed experience or result	They have finished.
Use modal + base verb for ability, permission, advice, or possibility	You can leave now.

Most simple sentences are statements that give information. Statements typically use falling intonation in speech and end with a period in writing. In statements, the subject usually comes before the verb.

To make a simple sentence negative, English often uses not with an auxiliary verb. If there is no auxiliary in the statement, English typically uses do-support with do or does in the present and did in the past. Negative sentences remain simple as long as they contain only one main clause.

Rule	Example
Add not after be	He is not ready.
Add not after a modal	She cannot swim.
Use do not or does not with a base verb in the present	They do not agree.
Use did not with a base verb in the past	I did not call.

Simple-sentence questions ask for information while still using one main clause. Yes–no questions usually use auxiliary inversion, placing the auxiliary before the subject. Wh- questions add a question word, and the rest of the sentence follows normal question structure.

Rule	Example
Invert be with the subject	Are you tired?
Invert a modal with the subject	Can they come?
Use do-support when there is no auxiliary	Does he work here?
Put the wh- word first	Where do you live?