Sentence Structure
Every English sentence follows a structure. Understanding the four sentence types — simple, compound, complex, and compound-complex — gives you the tools to write with clarity and variety.
The building blocks of a sentence
A sentence must contain at least a subject and a verb and express a complete thought. These are called independent clauses. A dependent clause has a subject and verb but cannot stand alone — it depends on a main clause to complete its meaning.
She laughed. (independent — complete thought ✓)
Because she laughed. (dependent — incomplete thought ✗ — needs a main clause)
Because she laughed, everyone relaxed. (dependent + independent = complete ✓)
The four sentence types
Simple sentence
One independent clause. Contains a subject and a verb and expresses a complete thought.
The dog barked. She runs every morning. Tom and Maria arrived late.
Compound sentence
Two or more independent clauses joined by a coordinating conjunction (FANBOYS) or a semicolon.
It was raining, so we stayed inside. She studied hard; she passed the exam.
Complex sentence
One independent clause + one or more dependent clauses joined by a subordinating conjunction.
Although it was raining, we went for a walk. She left before the film ended.
Compound-complex sentence
Two or more independent clauses + at least one dependent clause.
Although she was tired, she kept working, and she finished the project on time.
Basic English word order: SVO
English follows a strict Subject–Verb–Object (SVO) order. Unlike many other languages, changing this order usually changes the meaning or makes the sentence ungrammatical.
| Subject | Verb | Object | Other |
|---|---|---|---|
| The cat | chased | the mouse | across the garden. |
| She | sent | an email | to her manager. |
| We | bought | tickets | online yesterday. |
The typical order for additional elements is: Subject + Verb + Object + Manner + Place + Time
She (S) drove (V) her car (O) carefully (manner) to work (place) yesterday (time).
He (S) spoke (V) English (O) fluently (manner) in the meeting (place) this morning (time).
Sentence purposes
| Purpose | Name | Punctuation | Example |
|---|---|---|---|
| Make a statement | Declarative | Full stop | The train arrives at noon. |
| Ask a question | Interrogative | Question mark | Does the train arrive at noon? |
| Give a command | Imperative | Full stop or ! | Close the door, please. |
| Express strong feeling | Exclamatory | Exclamation mark | What a beautiful day! |
Sentence fragments: A sentence fragment is an incomplete sentence — it is missing a subject, a verb, or a complete thought. "Running down the street." and "Because she was tired." are fragments. Always check that your sentence has a subject and a verb and expresses a complete thought.
Tip: Vary your sentence types to make your writing more engaging. A paragraph of only simple sentences feels choppy. A paragraph of only compound-complex sentences feels heavy. Mix them — use simple for impact, complex for explanation, compound for balance.