This article is part of our Complete English Grammar Practice Guide — explore all grammar topics with interactive exercises.
English sentences follow a surprisingly consistent set of patterns. Unlike languages where word order is flexible and endings on words tell you which is the subject and which is the object, English relies heavily on position. Move a word to a different slot and you may change the meaning entirely — or produce an ungrammatical sentence. This guide breaks down every major sentence structure from the basic SVO pattern through to compound-complex sentences, covering clauses, common mistakes, and 8 practice exercises.
1. The Core: Subject + Verb
Every English sentence must have at minimum a subject (S) and a finite verb (V). The subject is the person, thing, or idea the sentence is about. The verb describes what the subject does, is, or experiences.
[S] Dogs [V] bark.
[S] The meeting [V] has started.
[S] It [V] rained all night.
Even the shortest grammatical English sentence must have these two elements. "Run!" looks like just a verb, but it is a complete sentence because the subject (you) is implied.
2. The Five Core Sentence Patterns
English grammar identifies five basic sentence patterns, each defined by what follows the verb. Understanding these patterns helps you recognise which elements are essential and which are optional additions.
| Pattern | Name | Example | Notes |
|---|---|---|---|
| SV | Subject + Verb | The baby slept. | Intransitive verb — no object |
| SVO | Subject + Verb + Object | She reads novels. | Transitive verb — has a direct object |
| SVC | Subject + Verb + Complement | He seems tired. | Linking verb + adjective/noun complement |
| SVOO | Subject + Verb + Indirect Object + Direct Object | She gave him a gift. | Ditransitive verb — two objects |
| SVOA | Subject + Verb + Object + Adverbial | We put the keys on the table. | Adverbial is obligatory with put/place |
SVO — The Default Pattern
The majority of English sentences follow the SVO pattern. The object receives the action of the verb. Crucially, swapping the subject and object changes meaning entirely.
The cat (S) chased (V) the mouse (O). — the cat did the chasing
The mouse (S) chased (V) the cat (O). — the mouse did the chasing
SVC — Linking Verbs
Linking verbs (be, seem, become, appear, feel, look, smell, taste, sound, remain, stay, get) connect the subject to a complement — an adjective or noun that describes or identifies the subject. The complement is not an object; the linking verb does not describe an action.
She is a teacher. (complement = noun)
The soup smells wonderful. (complement = adjective)
He became anxious. (complement = adjective)
✗ She feels badly about it. (badly is an adverb — it would modify the verb, not the subject)
✓ She feels bad about it. (bad = adjective complement describing her)
SVOO — Direct and Indirect Objects
Some verbs (give, send, show, tell, offer, teach, lend, bring, buy) can take two objects: the indirect object (the recipient) and the direct object (the thing). There are two equivalent patterns:
She gave him (IO) a book (DO).
She gave a book (DO) to him. (with preposition)
3. Four Sentence Types by Structure
English sentences are classified into four structural types based on the number and type of clauses they contain.
Simple Sentences
A simple sentence contains one independent (main) clause. It has one subject-verb relationship and expresses one complete thought.
The train was late.
Tom and Anna (compound subject) arrived and sat down (compound predicate).
Note that compound subjects and compound predicates do not make a sentence complex — it is still a simple sentence as long as there is only one clause.
Compound Sentences
A compound sentence joins two or more independent clauses. The clauses are equal in importance (coordination). They are joined by:
- A coordinating conjunction (FANBOYS: for, and, nor, but, or, yet, so) — always preceded by a comma
- A semicolon (;) — used when the clauses are closely related
- A semicolon + conjunctive adverb (however, therefore, moreover, consequently) + comma
I wanted to go, but it was raining.
She studied all night; she passed the exam.
The meeting was cancelled; therefore, we went home early.
Complex Sentences
A complex sentence has one main clause and one or more subordinate (dependent) clauses. The clauses are unequal — the subordinate clause depends on the main clause for its full meaning. Subordinate clauses are introduced by subordinating conjunctions: because, although, while, when, if, unless, after, before, as soon as, until, even though, provided that, etc.
Because it was raining, we stayed inside. (subordinate clause first — comma required)
We stayed inside because it was raining. (main clause first — no comma)
She passed the exam although she had not studied much.
Compound-Complex Sentences
A compound-complex sentence has at least two main clauses AND at least one subordinate clause. It is the longest and most sophisticated sentence type.
Although the project was difficult [subordinate], the team worked hard [main 1], and they finished on time [main 2].
4. Main and Subordinate Clauses
A clause is a group of words containing a subject and a finite verb. There are two main types:
- Main clause (independent clause): Can stand alone as a sentence. It expresses a complete thought: She left early.
- Subordinate clause (dependent clause): Cannot stand alone. It must be attached to a main clause: because she was tired (fragment — needs a main clause)
✗ Because I was late. (This is a subordinate clause, not a sentence.)
✓ Because I was late, I missed the bus.
✗ Although she worked hard.
✓ Although she worked hard, she did not pass.
5. Relative Clauses
Relative clauses are subordinate clauses that modify a noun. They are introduced by relative pronouns: who (for people), which (for things), that (for people or things in defining clauses), whose (possessive), where (for places), and when (for times).
There are two types:
Defining Relative Clauses
These identify which person or thing is meant. They are essential to the sentence's meaning. No commas are used.
The student who won the prize is in my class. (which student? — the one who won)
The report that you submitted was excellent.
Non-defining Relative Clauses
These add extra information about an already-identified noun. They are enclosed in commas and can be removed without changing the core meaning. That cannot be used here — only who or which.
My sister, who lives in London, is visiting this weekend.
The Eiffel Tower, which was built in 1889, attracts millions of visitors.
6. Adverbial Clauses
Adverbial clauses function like adverbs — they tell us when, why, how, under what condition, or despite what the main action takes place. They are introduced by subordinating conjunctions and can usually be moved to the front of the sentence (with a comma) or placed after the main clause (without a comma).
| Type | Common conjunctions | Example |
|---|---|---|
| Time | when, while, after, before, as soon as, until, once | Call me when you arrive. |
| Reason/Cause | because, since, as | She left because she was tired. |
| Condition | if, unless, provided that, as long as | I'll help if you need me. |
| Contrast/Concession | although, even though, whereas, while | Although it was cold, we went out. |
| Purpose | so that, in order that | She spoke slowly so that we could understand. |
| Result | so...that, such...that | It was so hot that we stayed inside. |
| Manner | as, as if, as though | Do it as I showed you. |
7. Common Sentence Structure Mistakes
Run-on Sentences
A run-on sentence incorrectly joins two main clauses without a conjunction or proper punctuation.
✗ I was hungry I ate a sandwich.
✓ I was hungry, so I ate a sandwich.
✓ I was hungry. I ate a sandwich.
Comma Splice
A comma splice joins two main clauses with only a comma, without a coordinating conjunction. This is a very common error in student writing.
✗ She studied hard, she passed the exam.
✓ She studied hard, and she passed the exam.
✓ She studied hard; she passed the exam.
Dangling Modifiers
A dangling modifier is a participial or adverbial phrase that does not logically relate to the subject of the main clause.
✗ Walking down the street, the trees looked beautiful. (The trees weren't walking.)
✓ Walking down the street, I noticed the trees looked beautiful.
8. Practice Exercises
For interactive word-order and sentence-building practice, try Unjumble, Complete the Sentence, and Sequence on LexFizz.
Exercise 1 — Label the Sentence Pattern
Identify each sentence pattern: SV, SVO, SVC, SVOO, or SVOA.
- The children laughed.
- She sent her friend a letter.
- The coffee tastes bitter.
- We placed the vase on the shelf.
- He reads the newspaper every morning.
Exercise 2 — Classify the Sentence Type
Write Simple, Compound, Complex, or Compound-Complex.
- The dog barked all night.
- I was tired, but I finished the report.
- Because it was raining, we cancelled the match.
- Although she was nervous, she performed well, and the audience applauded.
- He spoke quietly so that no one else could hear.
Exercise 3 — Identify the Error
Each sentence contains one error. Name the error type (run-on, comma splice, or sentence fragment) and write the corrected sentence.
- I love this city, it has great food.
- Although the film was long.
- She was late I was worried.
- When the alarm rang.
Exercise 4 — Combine Sentences Using Relative Clauses
Combine each pair into one sentence using a relative clause (who, which, or that).
- The man is my boss. He is standing by the window.
- I found a wallet. It was full of cash.
- She lives in a city. The city is famous for its architecture.
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